I'm a hoarder.
Everytime the wife and or I go to Wal-Mart or Academy or even the LGS, I buy $50-100 worth of ammunition and stack it away.
In those small amounts, the purchases don't hurt the budget and after a while I have a nice stockpile.
I bought a bunch of 45 not long ago and the kid sold me a couple boxes of 45 LC by mistake. So now I need to go buy a gun to shoot it ...
See how it works?