Heck, back in the '70s my gun club had a deal (through the Director of Civilian Marksmanship, I believe) for milsurp .30/06 at a penny a round. I bought all they could sell me, and THEN went out and bought a .30/06 to shoot it in. (Yes, it was corrosive. But boiling water to clean the bore was cheap. No, it wasn't match grade accurate...but it was "good enough for government work" and made me a better practical offhand shooter.)
Today, penny a round .30/06 ammo is long gone, but I still have that excellent rifle. And while I shoot all five gun categories of IDPA, I have to admit that I'm more likely to shoot Stock Service Revolver with .38 Special or one of the 9mm auto categories in large part because of the ready availability of cheap ammo.