First of all I would like to say that I am new to this site and don't know much about computers. I have a two main questions. First what would be a good gaming computer under 500 dollars? Secondly, I heard building one is much cheaper but how hard is it to build your own.(Keep in mind I have no experience?
keep in mind that for under $500 the system will be less able to handle high resolutions, high graphical settings and will need to be upgraded sooner than if you paid more.
at a bare minimum i would suggest:
mid level gpu
building a pc instead of buying one is not always going to save you money. it can depending on the parts you pick out but keep in mind that you can control the quality of parts you use. often major manufacturers use inferior parts so while you do not save monetary per se you get more performance for the same money.
as long as you take some time to get familiar with the basics of how a pc goes together and read a few guidebooks i would say even a 10 year old child can assemble one.
the biggest issue is determining which parts to buy and our active members in the systems area will be happy to give you an exact listing of what to buy.
the one thing you do need to know and follow is that you need to ground yourself (touch a metal object) before you handle each component. while static charge typically takes longer to build up than this it is a wise practice. either that or buy a cheap grounding strap (which connects your wrist via a wire to an alligator clip on your metal case).
as far as which components go where and how to connect them, if a guide leaves questions then ask away and most people here will be more than willing to answer them.
i've built 4 so far and i can say that its a much better idea then buying a pc from a vendor. if it was possible to do the same with laptops then i would have done this as well (but with laptops things arent so simple).