As I said before, I have near to no experience with this kind of thing.
Building a computer is incredibly easy, and for many people is actually a really fun thing to do. You'll be surprised. It's like putting together a small lego set with really big individual pieces.
By building your own computer you'll not only save money, but you'll also ensure that you get an experience that is more tailored to your own needs. You won't have to deal with removing 30 preloaded bloatware programs, and you'll get higher quality parts (if you buy them somewhere sane and not from some noname india brand on ebay) than what prebuilts get in general.