DickDunkin
Shooter
ebay, gun broker, basically any site I can think of let's you see old listings and you can use this to see price trends. I don't see it being an issue unless your some asshole who wants to buy peoples things for less then what the value is then try an relist it for profit.......WHO cares if people can see old postings with prices.......That tracking part ,is what a lot of folks dislike. When a deal is over it should be gone , as in forever.