I’d have to dig through the forum as it was about six months ago, but I sold Capcom IO with all the connections here for $150, and a Naomi 2 that has all three fans replaced, JP BIOS, and a black paint-job for $200. All three fans were over $100 collectively and had under 24 hours use so the price reflected that.
Please keep in mind to use SOLD prices on eBay and not current FOR SALE prices for reference. After that knock at least 25% off before posting it on a forum. Remember, you keep all the cash here, no eBay middleman cut.
Edit: edited my original thread way too much, deleted sold items. However, the Naomi 2 was sold to Quadratic and IO to KC-Slater.