When I was home and living with Mum, I would shop for her and managed pretty well.

I bought bulk meat, which is expensive, but you can split them and put them in the freezer for multiple meals. I kept an eye on the junk mail to see what meat is on special, and sometimes going shopping late in the day loads of things are marked down too.

Also bought the cheaper fruit & veg from the greengrocer

I wrote a list and STUCK TO IT....the minute you start scowling the isles, you end up with so many other things you just don't really need....like grain waves...mmmmm grainwaves!