So I'm seeking advice on how to go about this. I want to purchase a used part from a member of another forum. How does it work when you don't necessarily trust this person you don't know? Are expectations that he sends part first and on e I get it I send the payment? It all just seems a bit sketchy. Advice needed!
If it seems sketchy just don't do it. Normally you are expected to send the money first and then they send the part.
This. Also, what forum? Look at their seller rating (if applicable), join date, read their post and thread history (be snoopy), ask questions (if anything seems off, don't bother, communication should be thorough), ask to speak with them over the phone if that makes you more comfortable, and lastly...pay with a CREDIT card through Paypal if it is someone you don't know personally. This gives you two layers of buyer protection.
All of this, plus document as much of it as you can during the PayPal payment process so if something happens during the process you can file a claim with PayPal. I believe it was Ctracey (?) here that recently through a similar process and got his money back through PayPal.
Yep, as already stated, the buyer always pays first. Use a credit card through PayPal and don't pay via the "Gift" option and you have considerable protection against fraud. But the best thing to do is do some snooping into the user's past history and see if you trust them. Avoiding a scam or bad seller is always the best option, because even though PayPal/Visa can usually get your money back, it's going to be a hassle and take some time.
Search the forum for any indication of problems with the seller in the past. Some of the forums, I'm thinking of SubaruForester.org in particular here, has a feedback/rating system for just this purpose.