What should I buy. So would they want a computer that is repairable, upgradeable or compatible. Think about the difference between a Cadillac and a Chevy. Generally Cadillac's look prettier but are more expensive to run. Costing way more to own than a Chevy.
Computer stores sell upgradeable PC's because they make some income selling upgrades.
One is low cost for added features. Memory speed up your system for running games and all other tasks. A slower processor can come close to a faster one if it has more memory. That may sound logical, but never wait more than a year. Because prices always drop but technology also always changes.