Uh... It's not that it's not appropriate here, it's that it's inappropriate for a welcome topic.
This site is a community, not free advertising or a sale site. If you came here solely to sell them and nothing more, it probably won't work. But if you wanted to join here and that was the prompt, make some friends, you never know, maybe one would be interested if you mentioned it. But not your intro post.
I'd personally recommend EBay. Pokemon fans are there too.