Pet food is where supermarket price gaps get genuinely expensive

There is a category of shopping where people are unusually price-insensitive, and it is not the one you would guess. It is not wine, or chocolate, or ready meals. It is pet food.

The reasons are obvious enough once stated. The animal has a preference and will not negotiate. The product is heavy and bought in large formats, so it goes in the trolley once a month rather than weekly. And it sits in an aisle most shoppers walk down with a specific box in mind, not a comparison.

That combination makes it the single easiest place in a supermarket to overpay without noticing — and the numbers bear that out.

One product, £6.70 apart

Start with a single line. Gourmet Perle Ocean Flakes wet cat food, the 40 × 85g box:

Neither price is promotional. It is the same box of the same food, and one shop charges 43% more than the other for it.

That is not an isolated case. Sticking to identical multipacks, priced in the same week:

Across the whole aisle

Single products can be cherry-picked, so here is the wider version. Taking every pet care product we track at both Morrisons and Ocado — 86 products, matched on brand, name and pack size:

£44.75 apart, or 9.0%. Notably, 39 of the 86 were priced identically — so the entire difference comes from 47 products, and on those Morrisons led 37 to 10.

Widening to a different pair, the pattern repeats. Across the 93 pet care products we track at both Asda and Ocado, the totals were £653.13 and £718.60 — £65.47 apart, with Asda cheaper on 53 and Ocado on 18. In our full Asda-versus-Ocado comparison across 471 products of every kind, pet care alone accounted for nearly half of the total £141 difference.

For a category that is a small share of the products, that is a very large share of the money.

Why this aisle in particular

Two structural things are going on.

Format. Pet food is sold in 40-pouch boxes, 12kg sacks and 24-tin cases. A 5% difference on a £1.20 item is six pence and invisible. The same 5% on a £22 box is over a pound, and a household buying two boxes a month is £26 a year adrift on one line.

Frequency. Because the formats are large, they are bought infrequently — and infrequent purchases are the ones habit governs most completely. Nobody maintains a mental price for a thing they buy every five weeks.

39 of 86 pet care products were priced identically at both shops. Shopping around does nothing on those. It is the other 47 where the money is.

Deal case studies: when the cheapest shop changes

The basket result above is a useful baseline, but deals can move an individual product to another retailer temporarily. These July snapshots show why the cheapest supermarket can depend on the exact product and the day you buy it.

1. A Morrisons offer cut £3 from a Sheba multipack

Sheba Fine Flakes Poultry in Jelly, 40 × 85g, was £15.75 at Morrisons on an offer labelled “Now £15.75, was £17.70”, compared with £18.75 at Ocado. The immediate saving was £3, but it depended on the Morrisons offer still being live.

2. An Ocado offer reversed the usual direction

Lily's Kitchen Duck, Salmon & Venison dry dog food, 2.5kg, was £17.50 at Ocado on an offer labelled “Now £17.50, was £22”, while Tesco's shelf price was £22.80. That made Ocado £5.30 cheaper for this exact product during the offer.

3. One 3kg bag, three different prices

For Purina ONE Salmon dry cat food, 3kg, our July checks recorded £16 at Iceland, £17 at Asda on Rollback, and £19.25 at Tesco. The gap between the lowest and highest recorded prices was £3.25 — and the lowest price did not need an offer.

These are snapshots, not permanent rankings. Offers end, loyalty prices have membership conditions, and shelf prices move. PriceLens keeps those conditions separate: Tesco Clubcard and Sainsbury's Nectar prices are labelled as loyalty prices, not ordinary promotions.

What PriceLens lets shoppers do

PriceLens checks supported supermarket prices every 24 hours. Shoppers can track the products they actually buy, compare the latest shelf, offer and loyalty prices, and see which tracked retailer is cheapest at the latest check.

That is more useful than deciding one supermarket is “cheap” and another is “expensive”. The answer can change product by product — and a live deal can change it again.

What to actually do about it

The practical version is narrower than switching your whole weekly shop:

• Track the expensive repeat buys. Start with large pet-food boxes and sacks, where a single comparison can save pounds.
• Compare before the next reorder. Open the product in PriceLens and check which tracked retailer has the lowest current price.
• Check the price condition. A normal shelf price, a temporary offer and a loyalty price are not the same thing.
• Buy from the cheapest sensible option. Price and availability can move, so use the latest comparison rather than relying on a retailer's reputation.

PriceLens exists to help households keep more of their money during the cost-of-living crisis. Clear, current comparisons make it easier to spot the savings that are otherwise hidden in an ordinary shop.

The category totals above come from prices checked between 10 and 21 July 2026. The deal examples use retailer prices recorded during our July checks. Prices and availability can change, so compare the live listing before buying.