WordPress.com and wordpress.org are two different things. I did not know this until just now.
Turns out, you have to pay for the first one, and it has limited options and no ability to use plugins unless you fork over a slightly unreasonable amount of dough every month. The other is free (well, you have to pay for hosting, but I think I’m already doing that) and you can customize to your heart’s content. Downside: there’s no customer support. Which I’m not using anyway.
Now, to decide whether the hassle of switching is worth saving $8/month. I mean… I know it is, but: hassle.