if you need one that moves then this link has some good ideals on how to make one with a weasel ball.
http://www.varmintal.com/ahunt.htm Big Man on this forum made one but i can't find his thread.
truthfully, i priced making one and by the time you get all the pieces that you need unless you have stuff laying around. you could get a real one online. none of the stores near me carried the weasel ball and shipping is high for some reason. i kept searching and found one of the Mojo ones for around 30 bucks.