I got my ghost shrimp at Petsmart for .33 cents. Pretty cheap! one bit of advice I did discover when cleaning my tank last. I have two shrimp in a 3 gal tank. I put them in a small cup when I was re-arranging and cleaning my tank. Ghost shrimp can jump out of low water!
When I went to put them back in I was missing one! I looked all over and found him under my desk on the floor! I quickly scooped him back in the cup, went to the kitchen for a towel, came back and he escaped the cup again! He was on my desk! Sneaky little guy! But he seems to be recovering from his land journey.
Oh, funny thing, when he fell on the floor I instinctively reached down to pick him up, and he whapped my fingers with his tail! That hurt, too! Feisty devil!