If your budget is $150, then you need to look for used options on eBay. Look for Dell Optiplex or Lenovo ThinkCentre towers. You will not find specs that good in your price range. But maybe you can get a decent CPU and save money to upgrade your RAM later.

MAYBE you’ll get lucky and find an old Dell server on eBay. Sometimes IT guys will sell their company’s old server for a profit. But I personally wouldn’t buy one of those, the monthly electricity costs are stupid.