I got a 2U rackmount with 192Gi DDR4 for $1.1k USD in 2023. Around 1.5 yrs ago, server RAM could be had pretty cheap--especially slower LRDIMMs (I wanna say 512Gi DDR4 was <$500 USD). I checked a couple old ServeTheHome threads and seeing maybe around $50/32GB RDIMM although thought it was cheaper than that for a little while