Dell has the NVIDIA Quadro P2000 5GB GDDR5 Graphics card for $369 w/Free Shipping.
If you have a AAA membership, get the 10% Dell Coupon from your local AAA site. (Navigate AAA site and under discounts, search for Dell)
Once you have the code, use the Member shop link to start, takes off 5% (which I found in an older thread):
You should score it for $316 when you combine these. Plus tax if applicable. Not the lowest I've seen it in previous threads, but still a good deal if you're hunting for one of these cards.