Boo, wait a month or less. Skylake, the new Intel platform is starting to roll out the first few days in August so they're claiming, which means prices could go down on stuff available now, as well as the option to get the newest/better platform. Their i7 and i5 "gaming" or "enthusiast" cpu/mbs are coming out first too, so we should know shortly how it stacks up so far as performance/$ ratio. Typically prices do come down on the previous stuff. So, if you're looking for a sub 1500 or even a 1000$-ish rig, you probably will be able to get a decent i5 4690k with a really decent GPU like a 970 or whatever for a grand-ish. Or, you can choose the latest Skylake offering likely for around 1500$ for a decent system.
So far as building it, if that's your plan as well, LinusTechTips channel and several other gaming/tech youtube channels provide excellent how-to videos on building a PC, right from taking the empty case out of its box and starting from scratch up to installing all the current drivers and optimizing your OS and other stuff. Pick a couple good channels and watch those vids.
Also don't discount the importance of your monitor. A good gaming LCD is a huge part of the experience - 144hz can be found in 1080p for 250$ or less, and that's the way to go IMO unless you have extra $$ to move into the IPS/144hz/1440p Asus stuff now available. Having a 4k Acer Gsync I wouldn't recommend 4k...yet.
So, tl;dr, wait a few weeks, save some $, and then watch some instructional vids, and ask all the guys here for help if you want or need it.