KAC1911,
You will have no problem building your AR. I have done 3 so far and am working on #4. It is very addictive
The way I defray the cost is to let my friends try the 2 I built for myself, explain how "drunkenmonkeysimple" they are to build and before you know it they are letting me help them assemble their own ARs
I have bought lowers from Spikes Tactical
http://www.spikestactical.com/z/ind...ducts_id=309&zenid=ebu7j1rkrlj1erj6og5215sco0
and Essential Arms
http://essentialarms.com/LOWERSANDPARTS.HTML
In both instances, the process was the same: I "buy" the lower on line with a credit card from the manufacturer who then ships it to my designated FFL. I then go to the FFL, pay the transfer fee (but not sales tax unless the manufacturer is in the same state) fill out the paperwork and take the lower home. In my area its not hard to find an FFL that will do such transfers. Going rate is $ 15-20. The FFL might have to send a copy of his license to the manufacturer if they don't have it on file.
Building an AR yourself is great because your get to pick exactly what parts you want to use and can insure that each part is inspected, assembled, and tested correctly. Think "genetically engineered purebred" instead of "mutt"
Here are some pics of the first assembly I did. I Used an Essential Arms lower and a Bravo Company 16" carbine upper and auto bolt carrier group. The furniture and rear sight are Magpul.
I recommend spending some time at Ar15.com and M4carbine.net to get some great info on what are the most recommended components and best deals. Also, to get links to detailed assembly instructions and videos (very helpful!)
for most purposes all "in spec" lowers are fungible. I can recommend the above 2 from both personal experience and my research online. However, there are specialty lowers built to either aesthetic or specialized capability parameters that can give you just about any look or capability you could imagine and be quite pricey!
Have Fun!