I am on a tight budget too. I decide what I am having for tea and buy just that....then I head to the cheap shop where today for instance I needed dental floss and a mirror....a total of $6 ....the dental floss would have been that alone in the supermarket.
Buy the specials and buy in season. Frozen veg are much more economical and sealed soon fter picking so always nice and fresh.
I am down $80 this week....the ex said hed pay half my sons medical bills so spent my food money at the doctors....now he says he will get it to me.........so I borrowed from a bill that needs to be paid next Thursday....I can live on rice but when my son is here he needs real food...ah the cat and dog will do with dry food....it is just the way it is this week.
Try to stick to the basics and see how little you can spend...make it a game and all those special brochures plan your meals around them.