Just buy one of the bargain dremmel knock-offs that they sell. Aldi are selling one this week for £12!
I bought a £20 dremmel knockoff from Wolworths about 6 years ago, and it's still going strong (and it came with a flexi adapter). Probably had maybe 20 hours solid use out of it during that time.
For drop links and areas of rust however, you're better off with an angle grinder than a dremmel... you'll be there all day.