I use this to trim my beard if you're looking for something cheap: http://www.amazon.com/Schick-93002140-Q ... B001MIZMRK
The first one I had lasted about 2 years before the motor just wore down (I think?). It does a pretty damn good job for $15.00 (what I spend at the grocery store) so $5 at amazon is more than reasonable. I bought another one to replace the busted one. It's water proof too.
There is one thing that I think is weird about it though. After the first couple of uses, you'll notice the blades don't move as fast, but the battery is close to full. Just run it under some water with the motor on and it should speed back up.