We have been blogging a series on articles on building an AR-15 lower receiver from an 80% complete billet. If you don’t have the equipment to work with metal, EP Lowers sell a 80% complete fiber reinforced polymer lower that can be finished without a costly jig.
The company told me in an email …
They are constructed of a fiber reinforced composite more durable than any polymer lower available. Our product is made in the USA; features reinforced areas at the buffer tube and front pivot pin where other lesser lowers have failed. Also an integral over sized trigger guard. The fire control group area is dissimilar in color and is marked where drilling is required for easy completion. No Jig!
Their 80% polymer lowers are selling for $100 and are available in black or pink.
Read more here: The Firearm Blog