First of all, what kind of CS PPC are we talking about, so specs ?
You can sell here, you can also sell on
http://www.amibay.com/ register and do an introduction post and a reply as you need 2 post for PM to be active.
Amibay does however have the rule that you have to state a fixed price, here on Amiga.org you can just put it up here and ask for offers.
But as you don't want Paypal, a direct bank transfer is possibly the only option and thus limiting your target area.Look at it from a buyers point of view, here you have someone with 1 post stepping into the community.We have to go on good faith that you will actually ship the board to one of us without having any protection. I wouldn't go this way for the amount that it will sell, which depending on the model and RAM will be a substantial amount of money.I wouldn't send these kind of amounts on just good faith, no way!
I would list on Ebay with Paypal and then set it up with bidding and a good reasonable Buy It Now price.
If that price is good, it will probably sell within 10 seconds of listing.