The advantage of building your own PC isn't so much that you save money, as it often costs about the same as a pre-built machine. The advantage is that all of the money you pay for a home-built machine goes to buy things that you actually want or need, and none of it goes to pay for useless hardware or software that you don't want. So if you spend $1000 on a home-built PC, you get $1000 worth of things you want, whereas if you spend $1000 on a brand-name pre-built PC, you get $300 worth of things that you want, and the rest of the money is wasted.