Try local classified ads, or aliExpress. You can sell here as well, but I haven't tried it myself.
2Hack and Tony8690 thanks heaps for the info guys. It'll be a while before I reach 100 posts because I'm waiting for the Gateway New 3DS support and I've read of all the answers I have questions for and I don't want to make BS posts to reach the quota. I've posted the sky3ds on local auction sites so I'll see how I go. Again thanks guys