I have been spending a fortune on shopping (I reckon between £75 - 100 a week). There are three of us, me, dh and ds.
Anyway we are really hard up at the moment so I have really cut down. I have started shopping at Asda and planning meals. For instance if I decide that we will have a beef stew - I only put the veggies to go with that meal in. - I plan each dinner time like that. I also have started using their own brands - even their nappies which I have found quite good. I write a list and am really strict on what I buy.
On average now I am spending between £35 - £40 a week. I am so pleased. It is amazing the difference it can make in just going to a cheaper supermarket and watching what you buy can do. (also I make dh use a calculator as we go around poor bugger!!)