I'm agreeing with what has been said so far
The Arena has an awesome group of mods that really does keep the boards friendly and honest, and I have never seen an instance of someone trying to lead a non-pony person astray not be called on it
Once you do get the ponies photographed and listed, be sure to check the buyer's feedback by clicking on their screen name. Their profile will come up and in the fourth "box" down, you'll see a rundown of their Arena trader feedback (do keep in mind, people with little or no feedback aren't necessarily bad people to deal with, they may just be new to the Arena
) so you can make sure that they've only taken part in positive transactions
Selling ponies on Ebay seems to be pretty hit or miss, and while you'll miss the fluke chance of a bidding war if you list them here, you'll also be more likely to move the more common ones without needing to relist on Ebay