I'm sorry, but I don't really see any way around it. When you can't even scrape up 20-40 dollars for cheap shoes, there's a huge problem somewhere, and there's hardly anything to be done but do it and find out where your money is going. You can always check out eBay and stuff, but I hardly see you getting anything much cheaper than that.
Having a car when you're poor, for example, is something I have trouble not questioning. I'm poor yet relatively comfortable (as in, my living expenses are never endangered even though I don't have much left after then), and I figure I'm less poor than you with my monthly budget of 900 dollars. Yet I would never, ever, in a hundred years, even consider owning a car because of the tremendous money pit it represents. Even if I wasn't a public danger when driving a car.
Do you have both a mobile phone and a home phone? Do you have a mobile Internet connection? Do you have a TV subscription? Are you using needlessly fast Internet? Do you eat out? Do you spend on any entertainment at all? Do you smoke or drink? Do you eat meat? Those are all expensive things that you don't need. You may think you do, but you certainly don't.
This all comes down to basic budget management. If you can't have a budget that stays in the positive numbers after all unavoidable expenses so you can afford stuff like shoes, and ideally before they start hurting your feet, there's absolutely no way around it. You must find a way to fix your budget. I don't know the details of your situation, but there has to be a way to fix the numbers. And if there is none, make finding one your priority, and heck, ask your roommate/parents/whoever to give or lend you a bit of money because your feet are bleeding. When you need help, pride is stupidity IMO.
