I just saw this on GSMArena, so I thought I'd pass it along. I also just spoke with a Samsung CSR to confirm. You can now trade in any functioning smartphone to Samsung for a *flat* $200 off your purchase of any S10 phone, provided your phone still turns on (get to the home screen and function as normal); it's completely free of cracks; and you can factory reset it, removing all personal data and disabling software locks.
You'll get the discount off of your order and have 15 days to send in your trade in. If it's approved, you'll get an email to confirm.
I was curious to know if I'd be able to send in this pristine condition Nexus 6P that I'm using, and apparently I can. Now, I don't know what happens if your device isn't approved, and whether you'd have to pay the balance anyway, but it's something to consider. Since I'm in NY, a state sales tax of $71 still applies, so the final total for a base model Flamingo Pink S10+ comes to $871. Not *too* bad.
*Edit: I also read on GSMArena that Samsung's profits are still down about 14% compared to last year, so this has to be a way for them to try and recoup some of that, along with any other deals they think up until it's Note time.