If you are handy with tools it is quite easy to build an AR15, there are instructions available at AR15.com, and you don't need any special tools to do a basic build. In the process of assembling the lower receiver you will become familiar with the workings of the rifle and have a much better understanding of what is going on. You can get a kit from a reputable vendor such as J&T Distributing, the kit includes an upper which is completely assembled and headspaced, and the parts to complete the rest of the rifle, all you need from there is a stripped lower receiver. The lower receiver is the serial numbered part, the controlled part that must be sold or transferred by a licensed dealer. There are 2 small tools that make assembling the lower receiver much easier, they are roll pin punches, they are used to drive the roll pins for the bolt catch and the trigger guard, while not absolutely necessary, they make the job much easier and the total cost is around $11-$12 including shipping from Brownell's.
J&T Dist for a kit:
http://www.jtdistributing.com/
Eagle Firearms for a stripped lower receiver:
http://www.eaglefirearms.net/stag_arms.htm
Lower receiver assembly instructions:
http://www.ar15.com/content/guides/assembly/lower/
To assemble the lower kit the only special tools you need are the roll pin punches from Brownell's, the smaller one for the bolt catch pin and the larger for the trigger guard pin.
http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=5551&title=ROLL+PIN+PUNCHES
3/32 is #3 Roll pin punch
item #230-100-003
#3 Roll Pin Punch $3.75
1/8 is #4 Roll pin punch
item #230-100-004
#4 Roll Pin Punch $3.83
Small item shipping $3.70
total delivered $11.28
Notes: A chrome lined barrel is important on a military rifle used in the field where it won't get regular cleaning, unnecessary for an individual that takes care of their rifle, also chrome lined barrels are known to be less accurate.
Model 1 Sales doesn't sell rifles, only kits.
