You can get a couple of erasers in an office supply store or an art store. They're cheap.
The flash drive I got at an office supply store. I got a 1 gig since I barely ever use that much as I use flash drives for moving small files around. I don't need anything bigger for now. This is also pretty cheap.
Bonus points for the pink cap on it. It was like this flash drive wanted to be in an eraser from the beginning.