There are many threads on this forum as well as other sites such as reddit that all list many many many builds within that kind of price range. But I will tell you a little bit directly. At that range you're gonna want a Intel G3258 or an AMD chip, and probably a 260-270x Radeon GPU. Those two are going to be your most important. 8GB of RAM and a compatible mobo that you can OC well with and you're good to go with the basics.