Most major department (Wally World, K-Mart, Target etc.)stores carries Dremel bits. If you're near a Costco or a Sam's club they have a huge assortment of bits for around $20. I've got a Craftsman rotary tool with variable speed (a must have for any rotary tool) and have never had any problems with it. No matter what the speed settings are on the one you end up with, it's more about the amount of pressure that you apply with the tool that will determine that outcome of your work.
The best thing about working with plastic is that your tools last a very long time.
Unless of course you're using plastic tools.
![Tongue [:P]](/FSM/CS/emoticons/icon_smile_tongue.gif)
-fish