In case anyone is looking to pick up a 3090, there are several “renewed” ones on sale for around $1000 on Amazon:
https://www.amazon.com/ASUS-GeForce-Graphics-DisplayPort-Bearings/dp/B092T1CLK2/
https://www.amazon.com/PNY-GeForce-Gaming-Graphics-Renewed/dp/B092XB1JGD/
and so on.
Renewed != new, but still preferable over used cards by some random seller on ebay.
You can find used ones on there occasionally for $715 without a warranty or you can spend the extra $200-300 for the renewed to get the warranty it’s whatever you value most.