I owned this lens ("loaned" it to my daughter, so I suppose I still own it technically, but I will never see it again). It's one of Canon's best bargains. It's very sharp and has IS.
Maybe it's just me, but on a lens this cheap, I would pay the small premium to buy new from an authorized dealer rather than risk buying used. Particularly because it isn't the most robust lens in the world and you just never know what kind of abuse a used lens has been subjected to.