Sainsbury's have not had this offer on for a while now, so though I would post it and also unlike Tesco the price at my local hasnt gone up to counter act it.
When you spend £50 on shopping instore you will get a voucher with your reciept giving you 5p of every litre of petrol you buy and the voucher will not expire for 14 days.
Offer starts TOMORROW. FRIDAY 23RD OCTOBER!!