I dunno if you're just looking for used, and/or looking for something with lots of bells and whistles and set up for the GT, but I bought this basic all-aluminum EZ Hauler 5200 lb axles new from our local Texas Trailers in Nov '22 for $15,800 + tax/title: https://www.fordgtforum.com/forums/threads/gt-trailering-checklist.38773/ (I see it has since increased to $16,900) ... then installed full length E-track and a winch and made ramps. Mine doesn't have a driver's side access "escape" door, but they quoted me around $2,600 I think it was, as after the fact mod. So I just winch it in/out, for now anyway, until I decide to have the door added. Let me know of any questions.