Hey muskie, got an old computer collecting dust? I made one from an old hard drive, computer fan, and cell phone charger cord. It is very, very easy to make one.
im going to be making some with computer fans in a week if you want i was looking to sell for about $40 including stir bar and on off switch with LM317T controller and fancy blue LED
I am sure you have seen these threads already, but since its so easy and cheap to build one I just wanted to be sure. Hopefully this can help you save a little money.
If you don't have the fans or magnets, you may be able to ask your IT department at work or even check craigslist for old fans and hard drives.