Jack Monroe's Cooking on a bootstrap was written when she was claiming benefits in the UK and subjected to the sanctions regime. Some weeks she had very little money to feed herself and her child.

Because she was poor herself she does a good job of not requiring too much equipment - there's a fair amount of one pot stuff, or microwave only food. And she creates plans so that you use all the food you buy at the start of the week. Some books are cheap per meal, but you need to buy a huge quantity of something that you don't use again.

https://cookingonabootstrap.com/

Sadly, she's not a cook or chef and some of the recipes in the original book just don't work, so go careful. The reviews on Amazon can be useful.