The first generation new condition Tamron SP 24-70mm F/2.8 Di VC USD goes for $1100 at authorized dealers which can include some free accessories such as Adorama.
But if you are a more adventurous shopper, then to the eBay Deals we go, where eBay seller “QuickNDone” (99.9%) is offering the lens in new condition for $690 with free shipping in the Nikon system. Per the listing, the sale ends 9/20/17.
UPDATE: they also offer this in the Canon EF system for the same price.
Further down the product listing, under “Warranty” it says that you get either a 1-Year Tamron International warranty or a 6-Year Tamron Canada warranty, depending on location. They also offer a 30-day return policy.
This is a higher risk than buying in new condition from authorized Tamron USA dealers, that’s one of the reasons for the lower price. I believe “QuickNDone” is a Canadian seller.