In recent years, supermarkets have rolled out a wide variety of promotional offers. Bulk-buy promotions such as “Buy 1 Get 1 Free” and “Get 1 More for $1” can easily give consumers the impression that they are enjoying a discount of nearly 50%, while larger pack sizes are often perceived as offering better value for money. However, the Consumer Council’s survey on the online prices of 222 products sold by 3 major supermarket chains revealed that the “actual” discounts offered under some promotional campaigns were not necessarily as attractive as consumers might expect. For some products, even when “Buy 1 Get 1 Free” or similar bulk-buy promotions were available, the actual discount could be as low as 0% when compared with the single-item selling price during certain non-promotional periods. As for products of the same brand available in different pack sizes, there were instances during certain periods where the “unit price” of the larger pack was up to 35% higher than that of the smaller pack. In addition, pricing and promotional arrangements varied among supermarkets, and there was no fixed “discount day” applicable to all supermarkets.
The Council therefore reminds consumers that, when faced with constantly changing prices and promotional information, they should compare products based on their “unit price” and historical selling prices, rather than making purchase decisions solely on the basis of promotional formats or pack sizes. Consumers are also encouraged to make good use of the Council’s “Online Price Watch” (OPW) and its newly launched mobile application, which provides various new features including shopping budget calculation and target price alerts, enabling users to keep track of the price levels of products they regularly purchase and identify better times to purchase. Furthermore, many overseas countries and regions have already implemented unit pricing policies. Hong Kong supermarkets may consider adopting a similar practice to enhance price transparency and help consumers make more informed purchasing decisions.
The Council analysed online pricing and promotional arrangements of 3 major supermarket chains between September 2025 and July 2026 using online price data collected through OPW. Drawing on OPW’s 2025 browsing data, the survey selected 222 more frequently browsed prepackaged food and grocery items that were commonly purchased by households and available across all 3 supermarkets. These products were categorised into 24 product groups for analysis.
“Buy 1 Get 1 Free” Promotions May Not Be as Attractive as They Appear
Compare Single-item Prices During Non-promotional Periods
Bulk-buy promotions such as “Buy 1 Get 1 Free” and “Get 1 More for $1” often lead consumers to believe that products can be purchased at half price or close to half price. During the survey period, 48 products from 2 supermarkets offered bulk-buy promotions such as “Buy 1 Get 1 Free”, “Choose Any 2 and Get 1 Free”, or “Get 1 More for $1”. Analysis showed that, for some products, the single-item selling price remained broadly similar during promotional and non-promotional periods, resulting in an actual discount close to 50%, generally in line with consumer expectations. However, for certain products, the marked single-item price during the promotional period was higher than that during non-promotional periods, resulting in an actual discount far below 50% when compared with the non-promotional single-item price, which might not meet consumer expectations.
For example, a 150ml sesame oil was once offered under a “Buy 1 Get 1 Free” promotion at 1 supermarket. However, the single-item price during the promotional period was $20 or $22, significantly higher than the pre-promotion price of $10 to $14. After accounting for the promotion, the average price per item was $10 or $11, representing a maximum discount of only about 29% compared with the pre-promotion single-item price, which might not align with consumers’ expectation that a “Buy 1 Get 1 Free” offer is equivalent to nearly a 50% discount. Another supermarket had also offered the same sesame oil product under a “Choose Any 2 and Get 1 Free” promotion at a single-item price of $22. After accounting for the promotion, the average price per item was $11. Compared with the pre-promotion single-item price range of $10 to $14, the discount was only up to about 21%. Notably, under both promotions, the average price per item during certain periods was even about 10% higher (or $1 more) than the corresponding non-promotional prices, reflecting that bulk-buy promotions may not always offer better value than purchases made during non-promotional periods.
Similar situations were observed for other items. For example, a 410ml steamed fish soy sauce and a 280g rice vermicelli were offered under promotions such as “Buy 1 Get 1 Free” or “Choose Any 2 and Get 1 Free” at certain supermarkets respectively. The marked single-item prices during the promotional periods were significantly higher than those charged during non-promotional periods. After the promotional offers were taken into account, the average price per item was compared with the single-item prices before and after the promotion. The discount for the steamed fish soy sauce was only about 16%, while that for the rice vermicelli ranged from 0% to 29%, indicating that such promotions might not be as attractive as their marketing messages suggest.
Do Not Judge Value Solely by Pack Size
Compare Unit Prices Instead
When comparing products of the same brand and category in different pack sizes, consumers may assume that larger packs offer better value for money. In this survey, 15 product groups of the same brand and category but with different pack sizes were selected within the same supermarket. Their unit prices per 100g or per 100ml were calculated based on net weight or volume. Results showed that, for 7 product groups, the unit price of the larger pack was about 2% to 35% higher than that of the smaller pack during certain periods, indicating that larger packs do not necessarily offer better value at all times.
Taking bottled soft drinks of the same brand as an example, 2 supermarkets sold both 2L and 1.25L sizes concurrently during certain periods of the survey. Calculated on a per 100ml basis, the unit price of the 2L size ranged from $0.75 to $1, while that of the 1.25L size ranged from $0.68 to $0.95, making the larger size about 2% to 32% more expensive per unit. The 3 supermarkets also sold 405g and 150g full cream evaporated milk products at the same time. The unit price per 100g ranged from $3.43 to $4.91 for the 405g pack and from $3.33 to $4.33 for the 150g pack. On one particular day, the 405g pack was sold for $16.5 and the 150g pack for $5, with the unit price of the larger pack approximately 22% higher than that of the smaller pack.
No Universal “Discount Day” Across Supermarkets
Use “Online Price Watch” to Monitor Price Trends
Different supermarkets may implement promotional campaigns on specific days of the week according to their marketing strategies, allowing consumers to purchase certain products at lower prices. However, the survey found that the days on which the lowest average prices were recorded differed among supermarkets, and there was no fixed “discount day” applicable to all supermarkets. For instance, at 1 supermarket, about 39% of the products surveyed recorded their lowest average weekly prices on Wednesdays. However, when bulk-buy promotions were taken into account, the lowest average weekly prices for these products were more commonly recorded on Fridays and Saturdays. Among the other 2 supermarkets, 1 showed a relatively even distribution of products recording their lowest weekly prices throughout the week, while the other recorded the lowest weekly prices for about half of its products on Saturdays or Sundays after bulk-buy promotions were considered.
It is worth noting that competition among supermarkets has recently intensified, with various promotional campaigns being launched regularly, including storewide discounts, basket discounts, membership offers and payment-method rebates. The survey reflected that, as promotional formats become increasingly diverse, consumers need to compare the regular single-item prices and discounted prices more carefully, rather than relying solely on promotional claims.
Consumers may achieve greater savings if they know which days or periods supermarkets are more likely to offer lower prices and promotions. To facilitate smarter price comparison, the Council has upgraded the web version of OPW and launched a dedicated mobile application in August (available in Traditional Chinese, Simplified Chinese and English). In addition to collecting the prices of around 2,800 products daily from 9 online supermarkets, personal care stores, cosmetics retailers and pharmacies for consumer reference, the app also introduces several practical features. These include a “Budget” function that enables consumers to compile their regular shopping lists and compare the total cost of a basket of goods across different online retailers; a “Target Price” alert function that tracks price trends of specific products and sends notifications when prices fall to or below a preset level; and a “Scan Barcode” function that allows users to instantly access price information on included products and identify better purchasing opportunities. Consumers can also browse pages such as “Top Price Differences”, “Price Drops”, “Highlights” and “Tourist Top Search” to quickly identify products with significant price variations among retailers, products with substantial recent price reductions, and seasonal best-selling items. Search results can also be filtered and sorted by store, brand and price. OPW additionally provides the highest and lowest prices recorded over the past 7 days and 30 days, together with unit price information, helping consumers better understand price trends, make more objective comparisons across brands and pack sizes, and ultimately make more informed purchasing decisions.
Recommendations for supermarkets and retailers when providing pricing and promotional information:
- Clearly and consistently display unit prices (e.g. price per 100g or per 100ml) on online platforms and electronic shelf labels to facilitate product price comparisons across brands and pack sizes;
- Enhance price transparency when launching promotions or bulk-buy offers. Retailers should avoid substantially increasing single-item prices shortly before introducing promotional offers, as this may affect the credibility of the offer and consumer trust;
- Consider clearly displaying the discounted price per item on promotional labels to assist consumers in making informed and rational purchasing decisions.
Consumers seeking better prices on groceries and daily necessities should note the following:
- Do not judge value solely based on promotional formats such as “Buy 1 Get 1 Free” or “Get 1 More for $1”. Compare the non-promotional single-item price with the discounted per-item promotional price to assess whether the offer is genuinely attractive;
- When comparing products of different pack sizes, refer not only to the marked selling price but also to the unit price per 100g or per 100ml;
- Given the frequent changes in prices and promotional arrangements, regularly use the Council’s “Online Price Watch” mobile app or web version (https://online-price-watch.consumer.org.hk/opw), both available in Traditional Chinese, Simplified Chinese and English, to monitor the prices of frequently purchased products and identify promotional opportunities and savings.
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