Why buy? You can build a decent one for half of the price of the new one, but then again it depends on your skills and the time you have. Building a PC is a valuable experience, one learns a lot about hardware, which can be used in the future for your job as well. Start with the budget - how much can you afford and go from there. Good suggestions are - put new Linux on old hardware, they tend to bring a new life into the machines, something easy like Ubuntu-Budgie, Mint, Mate, Solus, etc. New PCs these days are relatively cheap, look for deals around holidays and you can snatch one for very little $$ if you don't like or can't do it yourself. To each his own.