Somebody asked if I worked for them...
No, I'm just an old fart who enjoys reloading ammo, and has been building up a stockpile since the mid 70s. Also, I have not done much shooting in the last few years, compared to the amount of loading I have done.
Go the gunshows, and always buy a few hundred brass, maybe some bulk bullets, and do this 3-4 times a year for over 20 years, and put together ammo when there is nothing better to do.
When you see than ammo can of 500 once fired .45acp brass for $20, including the can, well you just buy it. Well, then you need some 230gr RN, and you already have powder and primers, well, next weekend you have half a case of ammo. Go to the range and shoot 100-150 rounds, and the rest goes back into storage. Next time it might be .357, or .45 Colt. Then add in the occasional purchase of an actual case of something berdan primed, and over time, it adds up
For nearly a decade, my local Bi-mart store regularly ran a coupon special, Remington Viper or Golden Bullet, bricks for the same price, and always under $10 until recent years, so I always bought one of each, each time I went there. Besides, I was raising two kids who I knew would make inroads on my ammo supply when they got big enough, so it made sense to stockpile the rimfire stuff. Kids are grown and gone now, one a USAF Ssgt, and the other an airman currently in Baghdad, and I even have some .22s left over!
It don't spoil folks, at least if you store it right, even some of my 1980s handloads (before I used to get the cases really clean and shiny) worked just fine last spring. Also, I have an understanding wife, as long as my stuff doesn't crowd her space, I can have as much as I want (and can afford).
Another thing is I've been pretty settled for a very long time. Nearly 25 years in one house, so If you don't have to move your stash very often, you don't really realize how much you can accumulate over a quarter century or more.
There is a downside, and I cannot stress this strongly enough, ammo is heavy. If you store large amounts of ammo, you may get some wooden crates (I got 3 that used to hold GI 3.5" rockets) and they were great. Until the day I wanted some ammo from the bottom one and got careless. In the process of moving these rope handled wood boxes (essentially filled with lead), I injured my back. This put me out of work for some months, cost me a great deal of money (not to mention the pain), generally put a large hardship on my family, and put a serious crimp in my shooting and gun/ammo buying. Be careful!
It also taught me to use only GI ammo cans. I can still lift the .50 cal cans, even if full (if I am careful). So now I have a bunch of smaller cans. Makes it easier to keep segregatred as well. And it is what they're for. Nothing stores ammo better or more convienently than USGI ammo cans. It's one thing the Govt. got right!