Free: Contests & Raffles.
Mostly useless. Doesn't weigh much, so go for it.
I've tried it. Never got a response from birds I knew were there.
I have tried them but have never felt they had an impact on my bird in hand count. Have tried the Primos bellows style and Faulks mouth call. Unfortunately I lost my faulks call on the mountain before I was able to mess with it much. I have found the primos call sounds alright if you cup it in your hand. That said, it seems to be hit and miss. It did alright sounding recall after busting up a covey that broke into singles. That said 95% of the time in that situation the birds talk anyways. Or maybe its 100% of the time but sometimes they are too far away to hear. Fun to mess with though. 100% successful at getting my dog to come into the shop ready for action when I am playing around with it.
If your trying to stop those Chukers in their tracks, try a "Hawk Call" to help them lay low and let you catch up to the flock.
I bought one from BiMart several years ago. The wooden one with the green rubber top, that you tap the rubber top downward. It has worked several times for me when I was hunting sixprong creek near Bickleton.