Nah you don't. I bought an MSR stove that runs off gasoline you can fill up for $.10 at any gas station and then bought bags of rice and lentils that last a week for ~$10. Backpack on back, ask day labor place where to keep backpack when working, employer always had some place to tuck it away. I could earn ~120 / day and only need ~$80 a week to survive. Slept like a baby under my tarp.

If you do day labor all week you just made $500 and you only need $100 to survive the week. Pretty easy to sock money away that way... if you decide to rent a room a couple weeks of that gets you your first week in a weekly rental and from there you can clean up and get a regular factory job. I had a well oiled process that I ran that cycle quite a few times. AFter 1-3 months at a factory I would generally get a fork-lift job or something that paid even more and from there you're basically as rich as the average American.

Bonus: If you have HN skills your average wage from the fork-lift job will give you enough to buy a nice laptop, hi-speed internet and then a high-paying programming job -- although it's obviously not generally applicable (although I've done it).