Best Buy has the Apple iPhone Xs Max 256GB (Space Gray or Gold) for an upgrade price for Sprint Customers of $549.99 one time payment. No new line needed. $20 activation fee.
Yes this phone is 2 years old, and if you are adding a line or new sprint account, and those looking for BOGO, this isn't your deal as there are better offers for those situations.
But for those in the niche of only needing one phone or on a Sprint account like Kickstart (add line/cancel after ordering) or are leaving Sprint soon and don't want to finance. . .this is something to consider for a 6.5" iPhone vs. the price of an iPhone 11 Pro Max without adding a line, waiting on bill credits, etc.
Also available for same price Xs Max 64GB and Xs 64GB (but why)