I bought one carton of 100 cases for $60 from this website:

http://www.mediashelving.com/Merchant2/merchant.mv...

The cases are about the same size as VHS tapes. They have pieces of plastic inside to hold the games in place, and do a good job of it. They fit SNES, N64, and Sega Genesis cartridges. If you cut some of the plastic pieces out, they can also fit NES games. Make sure the cases you buy have sleeves on the outside to put the inserts in.