I've bought & sold stuff on Gunbroker for over 10 years. If you're selling, MAKE SURE you look at the final selling price on completed auctions, just so you don't price yourself out of a potential sale.
In all my auctions, I specify "Please DO NOT bid on my auction if this item is illegal in your location. If the item being sold is a firearm, please note that I am NOT a FFL holder - I'm just an unlicensed individual. If the receiving FFL holder decides that the seller/shipper must also hold a FFL, then you agree to pay any transfer fees that I incur in shipping the item to you. This fee is in addition to the price & shipping fees for the item being sold, as detailed in my auction." and "Please feel free to ask any questions BEFORE bidding on the item, and I'll be glad to answer them to the best of my ability. I have been active on GunBroker since 2002, and will do my best to earn an A+ rating on every transaction.
No international sales or shipping (sorry!).
Payment (Money Order or Cashier's Check only) and a signed copy of your transfer dealer's FFL and/or driver's license are due within 10 business days of auction close.
I work random days/nights throughout the week, so it might be 7 days or so following payment before I'm able to ship the item. If this is a problem, please do not bid on my auction. I believe in COMMUNICATING, and will do my best to keep you informed about the anticipated shipping date. Once the item is shipped, I'll let you know, including any tracking info."
Lots of words, I know, but it has worked to keep down the "flakes."
Make sure you include good pictures. Also specify the form of payment & a deadline by which payment is due.