Around £100 pw, occasionally it's higher. Me, dh, ds1 (8), dd (6) and ds2 (8mo). That includes packed lunches for ds and dd. I'm at home with ds2 so all our food too, plus nappies but am still bf so no extra milk and he eats small bits of our meals.
I get a tesco delivery and shop for special offers as much as possible, but there are certain things I will pay more for every week, eg always get free range chicken, organic milk and some organic fruit and veg- not all. So I buy say a salmon side when it's half price and portion it for the freezer, this week I got a big piece of pork fillet as it was a third off etc.
I do meal plan too, this week's meals-
Roast chicken dinner (roasties, carrots and broc)
Chicken risotto with leftovers
Pork fillet, rice, broc, sugar snaps
Salmon new pots carrots peas
Jkt pot beans cheese salad (every week)
Veg pasta dish plus salad (every week)
Something with sausages not decided yet
I don't go elsewhere for household /toiletries stuff so that's all in. Also includes some chocolate for me, sometimes beer or wine for dh.
If you search for similar threads, there have been useful ones where people say how much they spend and what meals they eat for that budget. I'm Not overly extravagant, but other people would come along and feed my family for half my budget. Tesco delivery works for me as I don't have time to shop around (as well as ds2 in the daytime, dad has recently moved to a care home and me and sis were previously caring for him at home, so are still very much involved in that).
I really love these threads for ideas, and I think it helps to know what types of meals people eat when they spend thriftily / wisely.