Which? found that shoppers who ordered everyday supermarket essentials from Deliveroo, Just Eat or Uber Eats could be paying at least 20% more, with some items more than double the price.
The consumer group compared the prices of up to 50 popular grocery items from four supermarkets – Asda, Morrisons, Sainsbury’s and Waitrose – against the three food delivery apps.
Which? also checked Tesco’s Whoosh same-day home delivery service to see prices compared with buying directly from the supermarket.
On average, Which? found that Sainsbury’s Nectar members had the most to lose by using a delivery app to fast-track their food shopping, as the supermarket does not apply its loyalty card discounts to delivery apps.
Members of the Sainsbury’s loyalty scheme would see the biggest mark-up with Uber Eats where they would pay an average 45% more.
They would see a 41% increase with Deliveroo and 40% with Just Eat compared with shopping in-store with their loyalty card.
Birds Eye Cod Fish Fingers (280g) were £3 with a Nectar card, but £6.25 through all delivery sites. Quorn Chicken Nuggets (300g) were £1.75 for Nectar card holders but £3.50 through the delivery sites.
The differences were less marked for those without a Nectar card, with customers paying 25% more at Uber Eats, 23% more at Deliveroo and 22% more at Just Eat.
Which?’s analysis showed that people shopping at Waitrose could be paying a third more (33%) by shopping through Uber Eats instead of directly with the supermarket.
The mark-up was less, although still significant, at Just Eat (30%) and Deliveroo (25%).
Two products were consistently double the price of buying directly at Waitrose: Pampers New Baby Nappies Size 3 (40 pack) were £12 through Just Eat and Uber Eats but £6 at the supermarket; and Tilda Microwave Basmati Rice was £2 from Deliveroo, Just Eat and Uber Eats, but £1 in-store.
Shoppers buying from Morrisons through Deliveroo and Uber Eats were likely to find a similar mark-up compared with buying directly at the supermarket (both 28%), while Just Eat was 26% more.
On one of the days checked by Which?, it found Just Eat price-matched Asda, so the average price difference was lower than overall. However, the mark-up of Asda groceries at Just Eat was still an average of 19%.
Asda groceries at Deliveroo and Uber Eats were significantly more, at 31% and 28% respectively.
Which? found that Tesco Clubcard holders would have paid a quarter more on average for its list of groceries by using Whoosh versus shopping directly with Tesco.
This was because some Clubcard offers were not available through Whoosh, including New York Bakery original bagels, on offer for £1 using a Clubcard at Tesco or £2.15 through Whoosh.
Non-Clubcard holders paid 18% more shopping through Whoosh, but were not missing out on the substantial savings that loyalty card holders were.
Which? did not include delivery charges in the overall totals as these varied depending on several factors including location and time of delivery.
Which? Retail editor Reena Sewraz said: “Shoppers won’t be surprised that buying groceries through a delivery app will cost more than popping to the shops or ordering directly from the supermarket and for many, convenience is priceless when they are pressed for time.
“But our research shows that in some cases customers could be paying more than twice as much for specific items as buying directly from the supermarket, so it’s worth working out how desperately you need to fast-track those nuggets, nappies and wine before you place your order.”
A Sainsbury’s spokeswoman said: “Customers can choose to shop with us in store, online or via third party apps for rapid delivery. Each of our services have clear, competitive pricing and regular promotions, helping customers to make the choice that’s best for them.”
Tesco said: “Whoosh is our superfast delivery service, getting groceries to customers’ doors in as little as 20 minutes. The prices for groceries delivered by Whoosh reflect the extra costs of rapid delivery and provide market-leading value when compared with other major services providing rapid grocery delivery.”
A Morrisons spokeswoman said several of the products highlighted by Which? were on promotion with Morrisons.com during September, so the data was not a true reflection of the price differences.
She said: “These premium services do come with some additional costs in order to offer fast, convenient deliveries which many of our customers appreciate. That said, our partners regularly run promotions offering free delivery offers or directly matching their prices to those found in our stores.
“Customers also have the option to shop with Morrisons directly in-store or at Morrisons.com for access to our home delivery or click and collect services.”
A Waitrose spokesman said: “Delivery apps offer a quick and convenient service. Prices are clearly marked, and reflect the costs involved in running this service, including assembling and packing orders.
“While some offers are only available when shopping directly with Waitrose, we have other promotions available via our delivery partners.”
An Uber Eats spokesman said: “These findings fail to reflect the breadth of inventory and deals available for our customers on Uber Eats.
“Every Uber Eats partner sets their own prices and we have clearly flagged in-store price match ranges available on hundreds of products. We also invest heavily in value initiatives like our weekly Fresh Monday grocery offering and further discounts for Uber One members.”
A Deliveroo spokesman said: “Deliveroo provides groceries fast and on demand, giving people the convenience they value. We encourage all of our partners to set fair pricing and we are always looking at new ways to ensure great value for our customers, including the integration of supermarket loyalty schemes and a newly launched offer of 50% off a range of groceries every Monday.”
Just Eat said: “Whilst prices are set by our grocery partners we ensure customers can access great value, as well as unbeatable convenience, with ongoing deals such as Half Price Wednesdays and encouraging our partners to price-match on the most popular products.”