How can i sell TC for USD?
Yes, just make a thread in "Items" board of Market, read rules first of course.
Not quite, you must always account for some risk involved (unless you like, sell the TC to your neighbor and get the money straight into your hands) with people unwilling to transfer you real money or doing chargeback shenanigans and so on. Market squad tries to unfuck majority of those nasty situations, but they still happen every once in a while.
In short, it's good to take a look at buyer's reputation and just use your intuition to decide if he's worth your trust.