As someone else mentioned, a new member buying used knives on here has most likely bought used items elsewhere before - usually, Ebay. I've sold ~$1,000 knives on here to new members, after confirming they have long-standing Ebay accounts with 100% feedback over hundreds of transactions. And, by confirming, I mean messaging them on Ebay to make sure it's actually them. All of those sales went perfectly smoothly. If a new member wants to buy a knife, and they can't (or won't) provide references to accounts with solid standing on other sites, then I get suspicious. It'd be odd for someone's first foray into the world of used items to be on BladeForums. As for trading, as others have mentioned, stay away unless the other person has a very strong reputation. I've only traded less than a dozen times, and I've gotten burned twice - both with new-ish members.