Thinking about buying a desktop PC

I'm probably thinking about replacing my 4 year old desktop PC, but it s hard enough that I only make $10k a year and most of it has to be through bills and college tuition. I don't have many options left and it seems that inexperience and delays are the main obstacles to finishing college. My associate degree did not do much in getting jobs that require a degree, so I work at an employment agency as a temp. worker. Guess I'll have to wait till the end of year to build my new PC.