I'm going to have to amend my earlier statement. The tablet isn't completely broken. In fact, the tablet itself is working just fine. The pen is just acting up. First thing that happened, one of the buttons popped out. This would be the smaller "middle click" button. I managed to fit it back in and put tape over it so I could still use it without having to worry about it popping out again. Eventually, the button completely broke, and I had to just throw it away. No big deal, I'll just reassign the middle click to the larger button and assign the right click to buttons on the tablet itself, since I don't normally use those anyway.
That worked for a while, and then the pen started acting weird. It would keep the click held down even when I moved the pen away from the tablet. Sometimes the click function wouldn't work at all. Dammit. So I did what any sane and rational person would do: I slammed the pen down against the desk over and over and then threw it at the wall in frustration. Then I calmed the fuck down, picked up the pen, and picked out the hairs that had somehow gotten into the hole where that broken button used to be. Apparently, that did the trick, because I haven't had any clicking problems since then.
I still intend to buy a new tablet once I have the funds. The pen is in okay shape, but besides the missing button, the rubber grip has rotted off, and the plastic has started to crack in places. The tablet itself is fine, but the fact is, it's getting old, and I don't want to wait for something else to break. It's time for an upgrade.