WARNING !!!! on purchases.

There are a few things you can do to make your transaction better for yourself.

Post count can sometimes scare off sellers, so get on the board and say hi, and participate a bit before selling or buying stuff.
Although I went to a gun trader forum and struck up a deal on my very first post ever there, met the guy and traded my pistol for a crossbow with a great transaction.
I made sure I posted pics and said the sale comes with a pivate bill of sale (makes them feel comfortable), told where I bought the gun from, and how long I owned it, told exactly what I wanted to trade it for and said I would meet them at their location of choice.
I made up my mind to only deal with someone there with a few good feedback scores.

That website has a transaction feedback score for each member in their profile.
There are three categories: Buy, sell, trade, and a space to leave a short comment like: "Bill was good to deal with, item just as described, would definitely do business with him again."
To see how they do this go to this link www.theoutdoorstrader.com