IMO, there's no reason to NOT get 'em from Ammo Can Rick, the Craigslist guy already mentioned. I've bought from him a couple times, and I need more. It's just hard for me to be in The Springs at times when he's available.

Be warned though, he's one of those guys that buys big lots of surplus stuff from the military/gov, and he's got a whole place just packed fulla tempting goodies! If you're a packrat like me, you might be in trouble. Either come prepared with enough cash to buy what you can't live without, or save yourself and just bring enough cash for the ammo cans you need.