I just did what felt like a big shop in Aldi - we had just come back from holiday so cupboards were empty. Bought washing powder & fabric softener too, although no cat food. Household is 2 adults, 3 Dses aged 9-14. Came to just over £70. I also picked up a few bits in Co-OP yesterday for £8 & I don't think I'll have to do a big shop next week, just top up of fruit & veg, milk & lunchbox fillers, totalling maybe £30.
For context, this is all breakfasts, most lunches (DH eats at work 2 days per week) & dinner for 6 nights (my mum feeds the DC one night, so DH & I had takeaway rare treat).
To keep costs down, I buy cheaper fruit- apples, bananas, plums etc & veg carrots, mushrooms, broccoli, frozen peas etc. 3 packs of meat eg mince for spaghetti bolognese/cottage pie, sausages & chicken drum fillets for curry or casserole. Fishfingers for the freezer. Then veg pasta 1 meal, often risotto for another, eggs for another. Burger/hot dog & hm wedges for Saturday nights or occasionally pizza.
I don't buy any brands, nor alcohol (we brought back a few 5 euro bottles from France but only drink once a week or so anyway). One bottle of fizzy drink for weekend. It really helps that none of my kids are fussy & we don't have any allergies. But apart from Christmas, I have never spent more than £100 on a weekly shop!
Another big tip is try to go in the evening & get reduced price items, especially if they will freeze. This was largely what my Co-OP haul was last night & will save us a lot (pack diced chicken, pork chops, 2 fish in breadcrumbs, loaf of bread, pack of fairy cakes, pack of cookies, cucumber, pack of burger rolls, oven chips, all just over £8). Then I will plan some meals around that so next week we'll have curry 1 night (hm), pork with mash potatoes & veg, DH & I can have fish & oven chips when boys eat with my mum. So almost half of dinners covered, which will probably include a pasta & a risotto.