I've never been an iOS or Mac developer, but I have had a few 5,1 Mac Pros. The release of m1 mac minis pretty much killed the used market for those, but you ma

I've never been an iOS or Mac developer, but I have had a few 5,1 Mac Pros. The release of m1 mac minis pretty much killed the used market for those, but you may still be able to find one for cheap. I was able to find a few 12-core 24-thread dual xeon models for around $250, but had to be patient. Add in 64GB of ECC RAM and an SSD upgrade, to Mojave or Catalina, and you have a beefy enough development system for around $500. Those 12c/24t will get smoked by an m1 mini for a lot of tasks, but if memory matters then it's probably still the best bang for the buck. Also, you'll need to find a GPU....