I did gig work while homeless. I pulled that link off a site I own called pocketputer.com. From there, you can also find the San Diego Homeless Survival Guide and Street Life Solutions, two other sites of mine.
It will also link you to Write Pay, a quick intro to working for Textbroker. You do need a bank account and a PayPal account to make money via Textbroker, but you don't have to apply for gigs. Once you have an account, you select work from a pool of articles. It is possible to make a few hundred a week if you apply yourself. It's not glamorous, but if you need to eat, it can cover that.