Thanks for the information, folks. I appreciate it.
I did end up spending a little bit of money on Christmas gifts (less than $100 in total) but mostly I've purchased things I need -- food, dental hygiene stuff, shelving for the house, shoes, a coat, and the pièce pièce de résistance: a treadmill! Wal Mart had it on clearance by mistake, so I got it for nearly $100 cheaper than they meant to be selling it. I've wanted a treadmill for a long time, because where I live, going out and walking isn't really an option. It's not a particularly safe area, and there are a lot of health issues that would make it even less safe. Especially if I get too far from the house and end up falling on my butt.
I've not decided if I'm going to try and use it until after I've gotten on a pain management program, but I'm really excited to get started. I need to lose weight desperately, I need to build up my wind, and I'm hoping all of these things will help me on the road to not needing SSI anymore. I don't want this to be a forever thing, I want to get back on my feet and go to school and have a proper life.
Thanks again for the info.