If you aren't sure, maybe you could use Paypal. That is a convenient way to purchase something and may provide you with a greater sense of security.
I have exchanged GCs with several members and had a very positive experience each time. I have not purchased anything from another member.
One member gave me their Cinemark GC (no places that accepted it in their area) and I offered something in return. They insisted that they did not want anything in return.
May your stuffing be tasty
May your turkey be plump,
May your potatoes and gravy
Have nary a lump.
May your yams be delicious
And your pies take the prize,
And may your Thanksgiving dinner
Stay off your thighs! LOL