5.56 is somewhat reasonable, I've been able to find ss109 and xm193 for under thirty cents per round for the past year or so. That's in bags of 1000 though. I got lucky and found some (5k) Israeli mil-surp green tip (ss109) last spring for sixteen cents a rnd. You can still find 7.62x39 steel case for around 210-220 per 1000.
The price off .22 has been so stupidly expensive that I don't even bother looking for it anymore, I've got a couple thousand rnds of 36gr hv kicking around, so if the price comes down, I'll start plinking again.
Pistol ammo is readily available, but anything other than range ammo is too pricey. I keep my carry gun loaded with the good stuff, but using h/p at the range is way too rich for my blood.
Reasons why ammo is scarce/expensive?
Some states are mandating microengraving - which drives up production costs.
The govt buying ammo through false fronts to provide clandestine support for various middle eastern proxy wars.
The biggie - home land security buying up over 1.5 billion (that's Billion with a B) rounds of ammo - which sounds excessive, but retrospectively is barely enough to shoot everyone in china once, or for the feds to shoot every american five times.
Hmm, sounds paranoid.: Source?
http://www.forbes.com/sites/ralphbenko/2013/03/11/1-6-billion-rounds-of-ammo-for-homeland-security-its-time-for-a-national-conversation/Some sources for bulk ammo:
Slickguns -
http://www.slickguns.com/category/ammoBulkammo.com -
http://www.bulkammo.com/Ammo To Go -
http://www.ammunitiontogo.com/