Hi everyone, I'm looking to get a mac as a new personal computer, as I'm tired of windows 8 and might even want to look towards apple products for software development. I do find mac's a bit expensive however, especially for my own needs. I have considered going on ebay and buying a used mac ( probably a mac Pro tower ) and upgrading it to today's standards if necessary. On the software end, will I be able to get the most recent version of mac OS X? I'm relatively new to apple products and don't know if upgrades are determined by computer specs or simply what model computer I have. Thank you!