I get mine from my LFS and they run me a quarter each. I use to get them a dozen or two at a time and some of my larger catfish will eat them. I've even seem some of my swordtail's and gourami's go for them. It's been about a month since i've purchased any and they have grown quite large and are now starting to breed in the tank. It looks like some of the baby shrimp are surviving and growing.
Thanks for the link, when I get my next tank i was going to stock it with 75-100 and see if i could cycle it that way, then transfer my fish over.
the petsmart i work at sells them for .30 each and usually if you ask nice we dont mind pulling out the ones with the eggs on the tails so you can breed them pretty quickly.
I get them at work for 30 cents a piece. I was so happy when the supplier started shipping them to us after a few weeks of not shipping us any. I usually buy us out when I get them and they are gone really quick. If I can't get live ones, I just use freeze dried krill. They are clear and make the substrate move as they pick through. They also make my puffer fat. All of my other fish in the tank (mono, scat, columbian shark) don't eat them, but do enjoy chasing them around.