The cheapest GeForce GTX 1070 right now is actually in an external box
https://www.pcgamer.com/the-cheapest-geforce-gtx-1070-right-now-is-actually-in-an-external-box/
Now is not the best time to buy a standalone graphics cards. As has been the case for quite some time now, cards are in short supply and, for the most part, way overpriced. If you absolutely can't wait any longer, however, and are in the market for a GeForce GTX 1070, the best deal right now is an external graphics box.
Specifically, Gigabyte's Aorus GeForce GTX 1070 Gaming Box (GV-N1070IXEB-8GD) is listed on Newegg for $600. At the time of this writing, there is no cheaper GeForce GTX 1070 on Newegg (unless you're willing to roll the dice with an open box model). The next lowest price is $700 for the card itself.