Frozen, uncooked shrimp is about all I use for catfish and I think it works great.

I just buy a bag at the grocery store. You usually get like 40-50 pieces of medium size shrimp for about $6 so it's not very expensive.

I just put it on the hook - nothing fancy. I find it works about the same whether it's fresh or has thawed and re-frozen a few times.

The other day we were floating on a creek and stopped to stretch our legs. We baited up with some shrimp and had 2 cats in about 5 minutes of fishing.