You get a coupon for 10p per litre off. You can use up to 5 coupons per transaction therefore getting 50p off the cost per litre up to a maximum of 100 litres. Qualifying products only.
Looks like a good deal but it may be just clever marketing. It costs me £2 to get to Tesco and back. The items in the promo do not look particularly good value. eg My local Iceland are selling the same Andrex for £3.50 (Tesco £5 and you have to buy 2). Asda are selling a four pack of Heinz baked beans for £1.50 (Tesco 4 packs for £9 to qualify). So you are paying for the petrol discount.
Looks like you have to spend £7 to get a 10p off coupon. £35 to get 5 coupons. So if you purchase 70 litres and the price of the petrol is not above average, you get your groceries for free, almost
Just be aware of use by date on coupon. I think they have been very sneaky as previous coupons except the last one have lasted 2 weeks from qualifying spend but my last one which I received from my shop on Thursday,12th July had to be used by 22nd July which made it only 10 days not the usual 14 days. I know we have to read small print but I feel that was sneakily done as how many people will have left fill up until close to empty thinking that the coupon will last the full 14 days.