I have to laugh at these things. Big store in town sells serialized full stripped lowers for as low as $39 if you buy 5 or more. I think they are $45 or $48 if you just buy one.
I love how these 80% lowers play to the tinfoil crowd by being able to purchase without a form/NICS check, but if you are a law abiding citizen with a clean record... is there any chance you haven't already been down the 4473/NICS road? You can't unring a bell. You can't get your virginity back.
I have picked up finished lowers for as little as $34 apiece.
But...
I also finished a pair of 80% polymer lowers last year. They cost me $39 apiece.
Ghost gun? Nope.
Fear of "Gubberment"? Nope.
Intent to traffic in illegal arms? Nope.
I just wanted something to 'play' with; and wanted to see if a ratty, cheap, bench-top Chinese drill press and a nearly-dead (probably counterfeit) "Dremel" could get the job done with no jig.
Both feed, fire, eject, and repeat. The first one had some issues, due to a combination of my failure at the drill press (poor setup) and a bad part (injection molding inclusion). But, I occasionally take the other one out. It looks like any other polymer lower, and it's only problem is that the bolt catch rarely works as intended and sometimes works as never-intended ... but that's a problem caused by the idiot that designed the mold (not something that's touched to finish the lower).
Even though both lowers could be seen as a waste of money, I don't regret the purchase or time invested. It was fun covering my basement in Nylon-66/6 chips and figuring out how to overcome some of the design errors in the part.
--
The beauty of the "80%"
aluminum lowers, for guys that just want to 'make' their own lower, is that most of the cosmetic, critical, and/or difficult work (such as magazine well broaching) is already done. All that's left for we peons to do is hog out some metal and drill a few holes in the right places. There's still enough work to be done, and it's still important enough to have a direct impact on function (or total failure), that there's satisfaction to be had from completing the part and turning it into a legal 'firearm'.
It's a bit like muscle car and hot rod guys building their own engines. Sure, there are crate engines available, engine builders all over the country, and thousands of good, running engines that can be dropped right in the car....
But what fun is that?
Just because I can't machine my own block and cylinder heads, or balance a complete rotating assembly, doesn't mean that I don't want to handle all of the other part planning, part procurement, assembly, inspection, priming, testing, and break-in.
Pride. Satisfaction. Knowledge of the equipment. ...And no one to blame, but yourself, if something goes wrong.
All of that being said...
There is one last point to be made:
Some cheap lowers really are crap - especially some of the polymer lowers. At one point in time, I had 9 polymer lowers (including the "eighty percenters"). Now, I'm down to three or four. I don't plan to ever buy another.
Those that I still own will probably stick around, but I won't be taking a chance on any others.