"now my question is how would i be able to buy the lower receiver of the AR-15? Ive looked around for an answer but i always see "you must be a FFL dealer or have a form 4 or be in law enforcement"
FFL holders can be found at gunshops. You must have the lower sent to them, then pick it up from there.
"...so is there no way for the average person like myself to own an ar-15? "
I see a CA,USA over to the left. Sorry, California does not allow Non-LEOs to own new AR15s, the AR15s in California were required to be registered years ago. Even if the assault weapons ban does sunset, you're still outa luck.
"because the ar15 is an assualt rifle, i know i have to come across paperwork and registering it and all that fun stuff so if you guys could help me here i would really appreciate it, thanks in advance "
Im not sure on the laws on buying a registered AR15 in California, but in states that dont have their own gun laws codified into law, there is little to none paperwork wise. I know that here in FL, 2 FL residents can do face to face purchases with no paperwork involved.
As for being the law abiding citizen you are, you arent completely out of luck. In California, an Assault weapon has detachable mag tech. speaking of course. So.... some guy got the bright idea of fixing a 10rd magazine to the lower, thus making is CA legal.
http://www.gogogadgets.net/index.htm this is the closest you can get to an AR15. Last thing: since the Fab10 isnt considered a assault weapon, you can put a retractable stock,bayonet lug, and a flash hider on it.