The saltwater ones seem to be almost impossible to get but the freshwater ones are pretty common. I get mine from my LFS or petsmart. However this site is good I believe.Where is a good resource for obtain the live feeder shrimp? Everywhere says out of stock for me, and my lfs doesn't get them.
Freshwater Ghost Shrimp; 100. Palaemonetes paludosus - Live Brine Shrimp
Live Freshwater Ghost Shrimp; 100 count; Palaemonetes paludosus
livebrineshrimp.com