Type
Add-ons that change what a console can do, like the Sega CD, the N64 Expansion Pak and the NES Zapper. Some only work with certain revisions of the console or with an old CRT television, so check what you'll plug it into before you buy. Others are copied by third parties, and the copies don't always work the same way.
3 models we cover.
NES
Add-on$15–$30 typical ask
146 on eBay
Sega Genesis
Add-on$210–$340 typical ask
41 on eBay
Nintendo 64
Add-on$60–$75 typical ask
152 on eBay