During a rather interesting period of my life I lived in a 3/1 with six other adults, and my total monthly budget at the time was $250. My share of rent and bills was ~110, food and transportation ate up the other ~140. Lived there for about six months. Looking back it wasn't the worst possible situation, so much as some of the worst possible roommates.
When I left I moved to an efficiency that cost 200/month including all utilities, with a shared bathroom and shared kitchen. I really did subsist on monthly trips to the grocery store (Ramen, bacon, instant mashed potatoes, cheap canned fruit, canned veggies, peanut butter, multivitamin, milk) and rolled my own cigarettes. This was all in 2003-2004. I was also at my thinnest then, cause I walked everywhere.