Buy when they are cheap and on offer, ignore when they up their prices, wait a bit till they are on offer again and then stock up. Not so easy when you are shopping working round a job, but when, as I am retired, there are many genuine bargains every week to be had.
Having time to study such items as shower gel, this week it was around £1.90 each but the ones I bought before Christmas were on a 2 for 1 offer, I stocked up then with a half a dozen, So I bide my time and wait for another offer and stock up again. Probably reduced again within 3 weeks.
Right Guard Men's Deodorant normal price £2.89 in Sainsburys but I have bought them as cheap as £1,44 or BOGOF. Bargains to be had on toothpastes, soaps and most toiletry products.
I am sure we are being taken for a ride by the supermarkets the secret is if you have the time and are canny enough to beat them at their own game. Buy when cheap, ignore when expensive. I have in my spare room a large stock of non-perishable items I buy in bulk when cheap and they are on genuine offers. Other favourites for huge savings I have are all cleaning products, particularly dishwasher tablets.
In the course of a year I estimate I save a massive amount by buying that way. In days gone by your money made more kept in a day to day current account but no longer that is the case any more. Try and match bank interest with the offers in supermarkets no comparison at all, the bank interest is crap, the supermarket savings leave them standing as an investment of your day-to-day money.
There is certainly a way at beating the supermarkets at their own game, it can be done it takes a bit of organisation and time though.