If you are not interested in building your PC yourself, then amazon offers some great pre-built computers with great performance and warranty.
Assembling your PC
CS:GO is not a demanding game. Any of these systems can run the game fine. If you want to stream you should go for at least the mid build.
These build are very balanced and will be good for any game, but CS:GO is very CPU dependent. So if CS:GO is the only game you play, you could spend a little less on the GPU and a little more on the CPU for better performance.
Welcome to the guide on how to build your new gaming PC