With the cost it is not worth it.
I got a few at onee time but you need a program or jig to do them and total cost was higher than just buying one.
Also dod not want the risk of a lower and no SN to invite added checking and wasted time.
Ive thought about doing it. Not to save money but just as a cool project. Some of then come with the jig needed and you just need a drill press to complete it.
I have done 10+. I use the 5d tactical jig. A little pricy to start off with, but virtually impossible to screw up a 80% with the 5d jig.
Yes, finished lowers are cheap, but having a gun that is not on government records is rewarding to me. Plus it make me proud to look at the finished product and know that I made it.
I recently completed another 5.56 and 6.5 Grendel. I plan on using the 6.5 Grendel for deer hunting, so I had a local laser engraver put some made up serial numbers on the lower. This just ensures that lower enforcement has serial numbers to run in the event I would ever get pulled over, but the government still has no record of these lowers since you make up the serial numbers.