[DK_]

Cost greatly varies depending on what parts you pick. AMD is cheaper than Intel, but when you get to the higher end CPUs, AMD can't really keep up. The other way around is true as well. Lower end, Intel is too expensive. But you can get a pretty great gaming PC for around $600.

I'd personally pick an Intel Skylake CPU, or wait until AMD release Zen in 2017, mainly to leave more options for upgrading in the future. Buying older hardware could result in you needing to buy completely new hardware in a couple of years. GPUs are gonna be the most expensive part of your build. Take a look at the RX480 or the GTX 1060. Both are great, new performance cards. An SSD is definitely worth the extra money, but PCIe-based M.2 is not yet.

Look around the internet for benchmarks, don't just compare numbers. https://www.reddit.com/r/buildapc is a great place to look for advice. Also check out sites like http://www.newegg.com/, they have deals pretty regularly.