I'm looking for some drum machine software that's either cheap, or free. Do you guys have any reccomendations? I want it to be reasonably simple, too.

Bluenoise mydrumset. It's similiar to EZDrummer, VST instrument with 24 bit samples, few velocity layers and built in mixer, where you can control volume for any of elements of the drumkit. Nice and simple to use. Might be a problem if you use Mac, it has only Windows version.

Yellow Tools Independence Free. That's actually sampler VST with two gigs of various samples, but there are three nice sounding acoustic drumsets there. You can hear it horribly misused (I didn't bother much with setting velocities) in the thing I posted here. Its interface looks kinda complicated but actually all you need is to click "browse" and pick needed drumkit from the instruments, then start tracking.

These are VST instruments. If you for some reason opt for standolne drummachine then there's simple leafDrums. In this case you need some samples to load into it though, since it comes with only basic set of them.

http://hydrogen-music.org/
I think it's a lot like Fruity-loops, but it's free.

Yay for open-source software

Acoustica Beatcraft. I use it. I like it.