What's a good/cheap electronic drum kit amp?

My son has an Alesis electronic drum kit and has been using his headphones with it. He wants some kind of an amp so he doesn’t have to mess with the headphones. I understand guitar amps aren’t the way to go but I don’t know what would be and I don’t want to spend a lot of money.

Any suggestions for a good entry-level drum amp?

You’ll want to use a drum monitor, like this one from Alesis.

Sadly $200-$300 is pretty much the cheapest you can go unless you look for something used. A guitar amp will not be able to reproduce the low frequency thumping that is pretty core to drum sets. If you think about it, a drum set really has a larger spectrum of frequencies produced than most other instruments, from the bass drum up to the splash cymbal.

I personally have a Yamaha MS100-DR that I really like. They make a smaller version - the MS50-DR - that is substantially less expensive and may be more your speed for an entry level setup.

Another option is a keyboard amp, since they have to reproduce the same range of frequencies, but I don’t see a keyboard amp being appreciably cheaper than a comparable drum amp while still reproing the low frequencies.

I was looking at something like this: http://www.amazon.com/Roland-CM-30C-Cube-Monitor-PA/dp/B000OY4WA6

That would do, right?

6.5" speaker? I wouldn’t want that for drums. If you want to save some bucks this is $199 at GC and has a 10" speaker, and could probably be found for cheaper if you looked around online.

This is timely for me. For the first time I’ve been trying external amplification for my Roland kit, and the Crate guitar amp I have hooked up sounds like ass. So it sounds like guitar amps are to be avoided generally.

I don’t know where Warning lives, but in Nashville the thriving used instrument market on Craigslist is to your advantage. It’s similar here in Austin, and I was just able to pick up a Roland KC-550 (available new for about $600) for $200. I tried out Roland’s PM line of drum monitors and thought they were inferior to their KC line of Keyboard amps. They start with the KC-60, but I think a used KC-150 is the entry-level sweet spot. They typically sell new for $375 or so but can be gotten used for less than half that. It has a 12" woofer, a separate tweeter, and a 4 input mixer (including XLR for Mics). Not necessarily something everyone needs, but it would let you connect an iPod to the amp or plug in that keyboard you eventually buy.

It depends what kind of volume level you want, but for amplified practice any decent solid state bass/keyboard type amp 30-50watts should be fine.
Roland Cubes come in all sizes, 70’s to 80’s peavey TKO series are cheap and plentiful, there’s a ton of choices, check out Musician’s Friend, Z-Sounds, or other online places for an idea of what’s out there.