I built my lower about a month ago, using a Del-Ton kit and a stripped S&W lower from the local FFL. After shipping and transfer the stripped lower ended up being cheaper so if you don't care the what the brand of the lower is you should check with your favorite FFL to see if they have a deal on something.
When people say anyone can build a lower, they are right I did it in a couple hours (I think).
My suggestion, rather than trying to hammer the roll pins use a adjustable pliers to squeeze them in place (wrap the “head” with electrical tape to prevent scratching.)
If you have a adjustable butt stock make sure you get the right size wrench, I didn’t and scratched the nut a bit (but that was the only damage done.)
I also used this video, didn't use as many of the special tools as the other videos.
http://www.lifelibertyetc.com/Home/Rang ... ippedLower