Usually priced around US$800, Dell is currently offering a stellar deal on an 11GB PNY XLR8 GeForce GTX 1080 Ti: the card is available now for US$633.99 with free shipping.
https://www.notebookcheck.net/Deal-GTX-1080-Ti-with-11-GB-RAM-now-available-for-US-634-with-free-shipping.232236.0.html