Always go for gtx 1060 3gb, even though it has 1gb less vram than gtx 1050ti, gtx 1060 has far more cuda cores than the gtx 1050ti.

• Gtx 1060 3gb - 1152 cuda cores
• Gtx 1050ti - 768 cuda cores

Therefore you can play games at higher settings with 1060 than the gtx 1050ti.

But try to go for the 1060 6gb model. Modern and upcoming games require alot of vram. Therefore getting the 6gb model will be a worthwhile investment.

1060 have better performance  than 1050 it only lacking with vram capacity but if you playing 1080p games its more than enough .

But if you going to do 3d works try to buy 1660 or 1660 ti because it is very newest and very powerful card.  1660ti is equal to 1070. And 1660 is equal to 1060 6gb