Buying a dremel from amazon...

I picked up a Pro Source Cordless Rotary Tool for 10 bucks at Big Lots. I've not only been able to work on customs but I've also done car repairs and parts cleaning with it. Its a handy dandy little gadget and comes with 60 bits and accessories from grinders, sander heads, cutting blades, drill bits, to all kinds of little different shaped heads. Its cordless, but the 2 hours of charging lasts about 30 minutes so I tend to leave the sucker plugged in while I use it unless I have to head outside to work on the truck. I been able to cut through 1/8th thick steel rods with it, which freaked me out, although it did take about 20 minutes, lol, for each rod. For another 8 bucks at Big Lots they have another 200 piece accessory kit with replacement parts and lots of cool extra tools.

And if it breaks they always have plenty more, but so far no problems with it even after repeated drops and abuse, my only gripe is that every so often you have to readjust the heads or attachments because the vibration and pressure you exert loosens them.

All dremels do the same job, they spin really fast, doesn't matter what brand it is, just remember that if it spins too fast it's going to melt the plastic instead of drilling/cutting it neatly. That one looks fine but pretty expensive, I'm guessing the flex-shaft is jakking-up the cost because those bits are nothing special. You don't need that many bits either, but if you're going to use the dremel around the house too then I guess you can justify the cost.

I use these the most: Standard Dremel-bits (to drill holes), Dentist's Burr (for making swivel-joints with screws), Grinder, Cutting Disk.

Seriously, that's all you need for customs, but if you're going to be adding lights and battery-packs and magnets, then you should probably get some router bits too, I've never needed them but they're perfect for implanting magnets.

I guess you could ask Jin Johns Jacobheimerschmidt for tips too, I hear he's not a jerk so he'll answer your questions :P