Back on the last weekend in October the bait camps closed early in POC. No bait. There they go $14 bucks. Like Bill said, it depends how big they are. It's a volume measure.
Dropping a frozen bottle of water in the my bait bucket helps keep shrimp alive longer. I've found that the warmer the water the less time the shrimp will keep.
I've seen guys using these in Florida. It keeps shrimp live for a very long time. Larger shrimp in the outer part of the cage, and smaller sized shrimp in the insert portion of the cage. Pretty neat set-up.