Other World Computing cuts up to 87% off a selection of new, refurbished, and used Apple accessories. Shipping starts at $1.79, or spend over $49 to bag free shipping. Each item is covered by a 90-day OWC warranty. A couple best bets:
Just an FYI, the Mighty Mouse was the most annoying mouse I ever owned. The scroll ball was really cool for the short time it worked. Get a little dust in there, though, and it stops working. Save yourself a headache, and don't buy this mouse. It's a novelty item at best.