I agree with Paradaz. But if you really need a card right now (APRIL 2018) then get a Nvidia 1070Ti. This article sums it very well and goes along on what has been posted here:
"Looking at the whole performance spectrum, the GTX 1070 Ti represents the best overall value."https://www.pcgamer.com/is-the-great-graphics-card-shortage-finally-ending/(PRICES AS OF APR 2018 IN US DOLLARS)
Nvidia graphics cards
GTX 1050 2GB: July 2016 MSRP $110, currently $140-$175
GTX 1050 Ti 4GB: original MSRP $140, currently $190-$225
GTX 1060 3GB: July 2016 MSRP $200, currently $250-$275
GTX 1060 6GB: July 2016 MSRP $249 ($299 Founders Edition), currently $290-$325
GTX 1070 8GB: June 2016 MSRP $379 ($449 Founders Edition), currently $489-$530
GTX 1070 Ti 8GB: November 2017 MSRP $449, currently $510-$575
GTX 1080 8GB: May 2016 MSRP $599 ($699 Founders Edition), revised Feb. 2017 to $499/$549, currently $600-$650
GTX 1080 Ti 11GB: February 2017 MSRP $699, currently $946-$1000
AMD graphics cards
RX 560 2GB: May 2017 MSRP $99, currently $115-$140
RX 560 4GB: May 2017 MSRP $109, currently $150-$175
RX 570 4GB: April 2017 MSRP $169, currently $260-$300
RX 570 8GB: April 2017 MSRP $199, currently $305-$350
RX 580 4GB: April 2017 MSRP $199, currently $300-$350
RX 580 8GB: April 2017 MSRP $229, currently $327-$375
RX Vega 56 8GB: August 2017 MSRP $399, currently $630-$750
RX Vega 64 8GB: August 2017 MSRP $499, currently $900-$1000