1. BUY & SELL LOCALLY if possible, you can see the product in person.

2. Contact the Community Organizer or post in the regional forum and see if the local people know the seller. If they know where he lives, even better.

3. If seller has very few posts, find reputable members who know him and his address.

4. Get seller's home phone number and verify it by calling. A phone number is better than nothing.

5. Do hw on the person, search his/her posts.

6. If you're selling and have many people interested, sell it to someone who is a member rather than a guest (a cc# is required and a trace is better than being left in the dark)

7. If skeptical, have the seller take a picture of the item with his/her username, date, and time. I know of a forum that requires this.
7a. If skeptical, don't buy.

8. If you're selling, make sure the check, money order, or paypal is cleared into your account before shipping (DUH)

9. Use Common Sense, if the price is too good to be true .... cmon now.

10. Pay with a credit card if going through paypal. Paypal does not help as much as a credit card company will.