Build one I built one and it was more than 50% cheaper than computers of the same level If you have a price budget I can give you a list of parts
*EDIT*
Since your using AMD, Like myself, and you probably don't want to upgrade your Motherboard just for the sake of Intel, I would Highly recommend the AMD FX-4100. It's cheap and very very fast. Perfect for play Minecraft or other Highly Intensive CPU games.
Either go with G.Skill or Corsair for 8GB RAM.
- Samo