Hey, Reddit! I need help purchasing a computer.

So, I consider myself to be a casual gamer. I play anything from WoW, to Skyrim, to Portal, to Minecraft. Currently, I use a laptop, a Compaq. I have about a 200-300 dollar budget. I don't need anything fancy, just a, preferably, desktop that I can game comfortably with without the constant, annoying lag I have to deal with. Any suggestions?