Harbor Freight sells one for about $15 with a bunch of attachments, and frequently puts it on sale for $8. It's the one with the wall-socket transformer. I've got one, and no, THIS IS NOT ONE OF THOSE.
This is a fairly heavy tool, variable speed, and it really has plenty of torque... it keeps its speed up well even when really leaning into it. I haven't had it long enough to comment on its long-term durability, but if it has any useful life at all it's a heck of a tool for the money.