9xx are last generation btw
10xx are current gen
if you're talking about first hand idk why but retailers don't discount them much and second hand they're still powerful enough to be sold at a moderate price.
They aren't that expensive, especially considering you can only buy them used nowadays.
But you should be looking into the Pascal series instead of the Maxwell series, anyway.
Specifically because you're almost never going to find new Maxwell GPUs that haven't been opened.
I'd have to agree with a lot of other folks--you ought to get something better if you're buying retail. If you're really set on getting one of the 900s, I'd try a resale site like Ebay or Amazon, so you're only paying like a third of the retail price tops.