It's wonderful that you want to start a gaming channel! I built my desktop gaming PC for $375 and it's pretty much running BF4 at Ultra settings recording at 30fps. It's just perfect for youtube. Look in my bio to see my specs. Also, don't spend too much $$ for equipment when just starting off on youtube. Try gradually buying things over time as you grow in subscribers. Also, you're gonna need a decent editing software to use. For future reference, I recommend Adobe Premiere Pro CC. Start off with Windows Live Movie Maker, I did for my first 100 videos Anyways, try using Fraps to record video and Audacity for audio. Merge the two tracks together and export in whatever quality you want (I prefer either 1280x720 (720p) or 1920x1080 (1080p)). Also, select a nice bitrate for encoding, around 10. I I hope you have fun starting up, but remember to be patient! Gaming channels take MUCH longer to grow than others. Have fun!

Well your budget is ok for a decent gaming pc. If you would like to build a gaming pc I suggest you choosing Intel and a GTX graphics card. Remember, Intel is better than AMD at gaming, same goes for the GTX being better than any other graphics card at gaming.