Depending what you do, you can get a long life out of a CPU. I had an i5 3600 for nearly a decade and probably should rebuild that machine into a nas. Running a similar vintage laptop as my workshop computer too, CPUs have been plenty fast with multiple cores for a long time now.
Second hand though would help, wouldn’t be surprised if we see a bunch of mk3s and maybe even some mk4 with their new printer coming out. I still use my mk3s pretty frequently, made a bunch of mods to it, still chugs along.