A "real" yelper does sound better, but these will do to learn on or see if you like the style of call.
$10 each shipped CONUS, payment in form of USPS money order or cash
The two bottom pics are videos. Click to play.
(http://i23.photobucket.com/albums/b378/nonnydarnell/kid%20yelpers_zpsv8md1dk4.jpg)
(http://i23.photobucket.com/albums/b378/nonnydarnell/th_410%20yelper_zpsinq48ofo.mp4) (http://i23.photobucket.com/albums/b378/nonnydarnell/410%20yelper_zpsinq48ofo.mp4)
(http://i23.photobucket.com/albums/b378/nonnydarnell/th_20%20ga%20yelper_zpsftasrsqw.mp4) (http://i23.photobucket.com/albums/b378/nonnydarnell/20%20ga%20yelper_zpsftasrsqw.mp4)
I know a ton of old timers that use a hen wing bone pushed thru a purple 16ga shotgun shell. Lot of birds have been killed with a very simple wingbone yelper. Thanks for sharing.