I eat what I can afford.
Largely:
White rice, stewed beef/hamburger (I can get several kilos of this, frozen in tubes, for 10 bucks), tinned soup, dried soup, frozen veggies, homemade bread.
That's about it. I eat a variant on that every single day. Sometimes, for a treat, I get mac and cheese.
As far as drinks go: White tea (I had some fans give me a large amount of a beautiful, very expensive silver needle white tea), jasmine green tea, iced tea (from powder) and water.