Excellent question. Given that there are many very good people in the world and given the nature of some people to be not so good and given how these auction sites operate, I do not think that I nor ANYONE else for that matter can recommend one to use. I would just urge caution in dealing with any of them, if you feel it necessary to use one; have seen enough of GunBroker to recommend staying away from that one entirely. Whoever you do end up dealing with, ensure that you have some safeguards in place, and on that subject, just the presence of a 'feedback' system is in actuality NO PROTECTION to a buyer whatsoever. Some of these scam artists can bury negative feedback quickly with alleged 'positive' feedback. Suggest you not believe me, scrutinize some of these sellers yourself. Start with some that have negative feedback, then inspect very carefully who it appears the negative feedback is coming from versus who the 'positive' feedback is coming from. Contact some of the buyers that have had issues and see what they have to say. Then see if you can actually contact and talk to someone that administers the auction site, think you may find that very interesting, let me know what the auction site administrators have to say about sellers that have been amassing negative feedabck for YEARS and still allowed to use the site. I am sure that there are many many good people selling on the auction sites that treat people in an ethically and legally correct manner, all i am advising you of is that it is my opinion that this is not true of all sellers, believe there are some bad ones, so proceed cautiously and protect yourself through every step of the process.