Chickpeas, in particular, are both very cheap and very nutritious. If you are trying to save money, you can get 1 lb of dry chickpeas for ~$2.50 in the US which translates into ~4 cans of chickpeas (1/2 a cup == 1 can).

Dried beans are a bit of a pain, but if you are looking to cut funds then you really can't do much better than dried beans.

Also, unsaturated fat is an important part of the diet. You need fat in the diet to absorb many nutrients. Skimping out on it can really negatively impact you. Olive oil and Avocado oil are my go tos. But you really wouldn't go wrong with peanut oil or canola.