On another forum people who want to buy, sell or trade items are restricted
They need a minimum of 100 posts and these posts have to contribute to the forum. Postings in 'Chat' or Jokes don't add to their total. Although this has nearly eliminated those of nefarious nature we still get a few trying but as they are after a quick buck they aren't prepared to hang around and get their postings total up the 100 mark. The honest person can quickly get to that total and can buy / sell / trade
Another restriction we have is that it is recommended that paypal is used for payments, and not the 'friends & family' bit, as it gives the buyer a certain amount of protection. Other payment types that can be used are, with the buyer's risk, postal orders or checks - either personal or bank. Anything else is generally forbidden* and the moderator looking after the selling area will delete the sales listing if it asked for. No warning. Its written in the rules
*I have now reached a level where I'm allowed to accept payment by direct bank transfer