The retailers that are know around this site will only sell to folks who are 18+ years old. You want to get yourself age verified and then you'll access a private area where you can dig into this. I don't recall those particular models being up for sale but then I don't spend a lot of time in the classifieds.
Other good ways to get in the loop are to check in on the local threads for games in your area and meet the other players face to face. Getting age verified is a face to face gig, and the games are good places to find the reps, and also to just see what kind of rigs folks are running.