Which ram should I get?

Even though I have been building for a very long time I have always been confused about ram speeds. I usually just pick the lowest timings and call it a day. I am going to do a complete AMD build with 570 chipset and a 3900x. I plan on getting gskill trident 4 sticks 32gb. This will be primarily a gaming rig. So can I get some explanations(if anyone has time) and recomendations on ram whether I should get ddr 3600, 2700 etc. and why? Price is somewhat of a concern, I would say 250ish is the max I want to go, however, I can save on other components if need be. TIA

I always read the supported RAM documentation from the motherboard manufacturer who's board I am using. Once I have access to that I then choose what I feel will be best for my system.

After doing some research I found that double sided or dual rank RAM is slightly faster than single sided RAM because it can read and write a tiny bit faster. I never increase voltage to my RAM which restricts me to lower clocked RAM. As such I am running my RAM at 2666 with a CAS latency of 15. Below is the RAM that I am using with my system.
https://www.amazon.com/gp/product/B00Q85WL8U/

The article below goes into depth regarding the JEDEC specification, memory speed, and latency.
https://www.gamersnexus.net/guides/3333-memory-timings-defined-cas-latency-trcd-trp-tras