I can get finished lowers right now 7075 T-6 Forged for 49.99 unless I wanted a unregistered gun, I wouldn't mess with a 80% lower for 100 bucks or more.
This is my latest build and is my personal gun...total cost even with the seekins muzzle break and larue rat stock is 682.00 total.
Here is my latest great find......I got this for free! yes I said free!