Everyone says "you don't save money building," but they always compare prices to Century WASR's. The fact is, if you are building right, you get something better than that when you're done.
So no, you don't make one for less than $300, once you count tooling and all that, but you get something a whole lot better than a Century AK for about the same price. I have never examined Aresenal or Vector AKs firsthand, but I think a fairer cost comparied would be $500 or more, in which case, you
do save a lot of money by builind them yourself...
Of course, I didn't save money on my first one no matter
how you compare them, since I had to buy the press, some jigs, extra rod to make a new barrel pin, a $20 reamer to adust the pin hole, and broke my vise trying to rivet with it...