Today you can buy DDR4 RAM for maybe 1/2 the price of DDR5. AMD's 400 & 500 series motherboards with the AM4 CPU socket use DDR4 RAM. And you can buy AM4 motherboards & compatible CPUs new today. While maybe not the latest & greatest, performance can be quite good. Demand for this older generation hardware has been so strong that Gigabyte is releasing a brand new AM4 motherboard model.
RAM prices are skyrocketing thanks to the demands from building more AI data centers. 32GB of the DDR5 RAM used on current generation hardware has gone from a bit less than $100 a year ago to a bit more than $400 today, and is expected to keep climbing in price. The older generation DDR4 RAM had risen in price earlier, again because of AI -- it just hadn't reached today's level of demand for more RAM, so DDR5 was not yet impacted, as manufacturers simply stopped making DDR4 because it wasn't selling as well. I suspect that DDR4 sales are depending on existing stockpiles, and that prices will escalate, though DDR4 was always cheaper than DDR5, and there are Chinese manufacturers of DDR4 so *maybe* there will be a continuing supply. [I *believe* manufacturing DDR4 takes less advanced tech than DDR5, and to produce RAM for AI takes more advanced tech than that. Since it's hard for Chinese companies to access advanced chip making tech, they *may* continue making DDR4.]