Didn't see this one on slickdeals but was pleasantly surprised to find this deal for Verizon on a shared family plan needing an UPGRADE.
They dropped the price of the XS to $859, and you can get a $200 Costco gift card even on an upgrade line. There is also trade available on top of that although I elected to keep my iPhone 6 with screen damage as a backup. A good condition iPhone 6 was worth a minimum of $100 but it comes as bill credits.
Assuming you don't buy something you didn't actually need at Costco with your gift card, that will bring your price of the XS with 64GB down to $659 (excl. tax, activation). Considering very good condition iPhone X 64GB sells used for values approaching $600 seemed like a no-brainer to pay just a bit more for a brand-new XS.
My local Costco was down to just 7 XS's remaining.