I shop in asda. We spend approx £60 a week on average but it can be a lot one week and then considerably less for the rest of the month.
I bulk buy the massive bags of pasta and rice, it works out cheaper.
I buy asdas own brand washing powder as its only £5 and does as well as a £12 branded box. I buy asda toilet rolls and kitchen towel.
I don't buy masses of cleaning products, the multi purpose liquid is fine for everything.
I don't buy jars of sauces, cheap passata plus some fresh tomatoes, onion, garlic and herbs makes a much nicer and cheaper version.
I buy asda gold blend coffee, it's half the price of the brands.
I also buy very large joints of meat or big multipacks which are cut up or split down into food bags for the freezer. I buy the cheap packs of bacon which is as good as the expensive stuff and use that either for sandwiches or cut up to make a risotto.
There are four of us, two adults, a teen and a 9 year old. We also have two cats.
I'd suggest buying own brands, looking at what you are eating and seeing if there's a cheaper way of doing it by substituting an expensive ingredient for a cheaper one.