Yes, it can, but not very nutritiously. It is very possible to do it if you move to what is essentially an almost all-starch diet and buy in bulk, adding in vitamin intake from tablets. A 50-lb sack of regular rice is $16; and will provide 550 1-cup cooked portions. At my poorest I regularly ate "rice and gravy" several times per week; large canisters of powdered meat-flavor gravy mix cost about $5, and each will make about 13 cups of gravy. You need about 1/4 cp for each portion of rice to make that. So, the rice will last a family of 4 for about 40 days if carefully portioned, and you would want several canisters of gravy mix to make it tasty. Even with buying vitamins and powdered milk for the kids, you would probably have a bit of cash left over.
No one WANTS to eat this way, but in my lifetime I've known a lot of people who had no choice.