What's the best graphics/video card for me?

I'm looking for a graphics/video card that is cheap but effective. I won't be playing high end games like battlefield, i will most likely be playing games like minecraft, garys mod, and war thunder.
1) what benefits do i get with a graphics card
2) what is a good cheap one for high fps
Note: i would LOVE to keep it under $100 but if needed can go over a little

For your purposes you will be good to go with an APU like the A10 series. Any of those will do.

If you already have a processor, get a cheap gpu like the Nvidia GT 630. If you want the absolute best fps for war thunder and such graphically intensive games, you should get a better card like maybe an AMD 7770 or 7790.

Minecraft is not very graphically intensive, But war thunder can make an APU choke. A dedicated GPU is best.

A GPU will help you in getting better graphical computing for games, meaning less lag, better fps and higher graphical settings. Also, it will improve video decoding, so videos will run better and you can easily play 1080p video with a GPU without lag.

NVIDIA GeForce GT 630M
FOR:
Intel core i5 processor
any latest laptop
Windows 7 or 8
ITS 4 MIDDLE CLASS LAPTOPS
PRICE IS NORMAL 80$ (NOT SURE)
100 FPS?