I agree with OmegaStarScream- as long as the things you're trying to buy or sell aren't illegal, the escrowers
in the list provided should be able to service your request and escrow your transaction(s) at a low price, and the users on the list are legit. I would go to another provider for whatever you're trying to buy that accepts clearnet escrow if possible.
There are indeed many scam services on Tor, especially mixers, but there are mixers that legitimately operate on Tor. Bitblender (
http://bitblendervrfkzr.onion/) is one example.