https://www.serverbuilds.net/ which is an offshoot of https://www.reddit.com/user/JDM_WAAAT
They also have a Discord.
r/homelabs is also good, but it can be more rackmount focused as far as gear recommendations.
Re:DRAM Prices in ‘Freefall’
by fivefive55 on Thursday March 07, 2019 @04:53PM
(#19332894)
I just found this subreddit yesterday, seems right up your alley.
Recommendations on sites/forums?