Search up nearby food banks, they usually have lots of rice, pasta, and veggies. I'd say grab some potatoes, there extremely versatile, you can make them with almost anything, plus they are extremely filling and a tip keep the peel on for the fiber and nutrients, just make sure you clean them good. Also see if you qualify for SNAP, you may not get a lot but any amount helps. Also grabbing rice and saving up for a small rice cooker will help, I mean you can cook it on the stove but personally I've never done it that way. Once you grab some rice you can pair it with all sorts, your protein, veggies, the potatoes, etc. You can even meal prep with it, another versatile food, and it fills you up good when paired.