walmart has the rdx or something. it's basically a dremel and is real cheap. supposedly pretty strong too. three rpm modes. doesn't come with any cutters though so you'd need to pick up a mandrel and some discs. would run you maybe $35-40 in total. I've got one and it's pretty decent, although I'm absolutely terrible with it and only use it for odds and ends. Ended up getting a holesaw to do what I needed to do (hah burnt through an old power drill trying the first time too)
I have just dremeled into my motherboard tray, about the only bits I used were a drill for marking the corners of my holes and a reinforced cuttingwheel for the cutting. Also I got at set of small keyfiles to finish up the work. I think that I paid around $60 for the Dremel with bits on sale, the fileset was something like $6.