I got myself a Wacom Bamboo Capture I bought last July. The tablet itself was $75, and the pen was around $30. I've got no issues with it. It has pressure detection, which is a must have if you're gonna be arting. Easy to install the drivers, but the default settings on it have haptic feedback that causes some bad lag. Just disable it and it'll be fine.
Just looking at it now, I think it's around 8 x 5".