Used to be that milsurps were sold by the pound. That's approximately 50 years ago. The days of cheap surplus rifles were over 35 to 40 years ago.
Cheap is definitely relative though. I paid $175Cdn.(lotta money at $6.25 per hour or less.) for my M1icon Rifle and my '03A4. Over 40 years ago for the M1, about 35 for the Springfield. To replace 'em would be roughly $1500 to 2 grand for the M1. Not sure I could replace the '03A4 for under 3 grand. Probably not in Canadaicon at all. And I'd have to sell a kidney to do it.
The thing is that there's no place to order any kind of milsurp. The old distributors cannot buy 'em any more. And the Third World Debating Club has ended the international trade in small arms. So what is Stateside, is all that's left. And none of the firearms you want have been made for 70 years or more either. It's become a case of, "If you want to play, you have to pay." Even then the supply is limited.