Light work and General Home Use
Most PCs for this will run about 400-500 Dollars with Windows. (with out a screen, mouse, keyboard etc.) This will be plenty for browsing the web, watching videos, getting some work done, and even light gaming!
Entry level Gaming PC
This will add the benefit of a faster CPU and the addition of a graphics card. This will be able to run games like Call of Duty, Battlefield, GTA V, and Skyrim on medium- high settings. Minecraft you say? Pppfffttt... Play Minecraft as smooth and fast as anything. This will run you about $500-$700. (It will make the Xbox One and PS4 look like last generation)
Ultimate Rig
You will be blown away with speed and graphical capabilities. You will be able to run any game with the graphics turned all the way up. This PC will also last you a long time with no worries about having to upgrade anytime soon. This will be pretty expensive running in at $800-$3,000 depending on how hardcore you are willing to go. (We can help you make the decision on what is best for you.)