They work REALLY well if you practice with them. You can pretty much make any noise you want with them. I use the same diaphram call for a cow call, bugle, etc. You can sound like a herd of cows if you need to. I think mine cost $6.95.

Of course I still can't make a good chuckle or grunt with it yet!

I prefer the ones with the metal or plastic bridge on the top, I can't stand the buzz on the roof of my mouth.