I have an air belt sander that I got off ebay. A cheap unbranded one and it is fine, works well. The only thing is the belts don't last very long and if you are grinding back welds etc then I think an angle grinder with a flap disk if you have access or a die grinder with Rolco discs is a better alternative.
I agree with this statement. Personally in my limited experience all the tools mentioned above are worth having for different jobs. As has been suggested elsewhere I bought cheapish unbranded kit and never really had a problem with any of it, but it never took a huge hammering either.
