If you know how to budget, anyone can do it.
Let me just budget the money I don't have. Between gas prices, rent and utilities, my grocery funds are really strained.
being poor sure makes it harder, and not as much variety, but not impossible
like i always hear people say "oh mcdonalds is so cheap" but for not much more (of even less, depending on where you go and sale prices) than the price of a single dollar menu (do they even have that? someone told me it was 1.50 now) burger i could get a yogurt cup and a fruit (or two, depending on what kind and sale prices), and have a much healthy, and also more filling, lunch. For dinner, maybe add a few eggs and another fruit. And more filling than a couple dollar menu burgers. I've done that many times.
Oh stuff no, I never eat out, going out to eat is way too expensive.
I come up with a lot of cheap meals by using a mixture of processed and fresh produce.