first may i ask you where are you from ?
now the best graphical cards are :
- AMD RX 470/ RX 480 8GB
- AMD RX 570/ RX 580 8GB
- GTX 1060/1070
or you can wait until the special mining cards will be avalible on market,
for more information about them : https://videocardz.com/70520/nvidia-p106-100-cryptocurrency-mining-card-tested