First, is the marketplace at torrentinvites.org legit? Second, is it dishonorable to do such things? Third, how to avoid scams? Fourth, are there alternative marketplaces to have a sense of whether the price is right?
UPDATE I wanted to thank all for the feedback, you made me change my mind and saved my ass from some costly frustrations… good thing I asked here first!
Just as a sidenote if you really want to go that route there are some trackers that can be joined with a donation upfront. It is better to join trackers with an invite, or wait for open signups, or interview to join if possible, but if you’re really thinking of going that route at least this won’t break any of the tracker’s rules.
See https://opentrackers.org/tag/donation-signup/ for example.
PS - Joining a tracker that way does not make you immune to their rules just FYI, you’ll still get banned eventually for not seeding/maintaining ratio & things like that.