If you're new then I should tell you that for most gaming, you will need a videocard. Your i5 is powerful enough to use either a 3gb 1060 or 6gb 1060. Of course, you can save money and get a 1050 instead.
At 1080p a 1050 will need to run at low-medium settings in demanding games. That's because it only has 2gb vram. The 1060 will run at medium or high settings at 1080p, while giving better performance than the 1050.
If the games you plan to play are the newest, most demanding games(like the new Assassin's Creed) then yes it's worth getting a 1060. If you will be playing CSGO and League of Legends types of esports games, you will probably be happy with the 1050.
The 1050 Ti is sort of halfway between them. It's faster than the 1050 but slower than a 1060. If I had your i5 I'd either save the money and get the 1050 or get at least the 3gb 1060, I would not bother with the 1050 Ti.