See if your local computer store [best buy or whatever] can build the parts for you. And get the estimate price for them.
Then compare the price to building it yourself, (Such as, the parts you buy and stuff)
Then, compare it to just buying it. Which one is cheaper.
Which one will get you the best quality.
When people say just YouTube some vids, sure. But sometimes they're unreliable. It all depends on what vids you watch.