I bought a Black & Decker rotary tool for pretty cheap from them back when they used to have a store at the nearby outlet mall. You definitely don't need a Dremel-brand tool, but just don't buy a cheap POS, like from Harbor Freight or something. I would just see what the local hardware stores have. Sears, especially.
When I had to add jacks to the back of one of my consoles, I used a drill to cut little pilot holes, and then made them bigger with the Dremel.
Chris