I guess it really depends on 2 things: The brand & the amount you are willing to pay.
I use this type (LINK) and absolutely LOVE it - I use it all over the place. It uses rechargable batteries that are use for other tools as well - VERY convenient.
But if you're looking for a smaller, self contained one: Make sure you know which typre you want 1st - read reviews at sites that sell them.
Now, I've bought tools off Ebay before - Make sure you get a picture of the actual item before you bid too.
Also, be careful, since cordless Dremels seem to make a habit of breaking or malfunctioning. If it starts screwing up after you buy it, don't disregard it as a one-time thing.
i personally use the new awesome Dremel 4000 with a 65 tool case, its range of power is 20,000 RPM to 40,000 RPM. I have a spare Dremel 300 that has malfuntion.
i personally use the new awesome Dremel 4000 with a 65 tool case, its range of power is 20,000 RPM to 40,000 RPM. I have a spare Dremel 300 that has malfuntion.