This prop is easy to throw together and the cost is comparatively low for the effect. Here's your parts list: 4 feet PVC (I used 1/2" instead of the usual 3/4". I feel the less PVC to fill the more air that goes to the whips) 1/2" PVC end caps x 2 2 Way Solenoid Valve (Mine is a Monster Guts)...

http://www.shutterfly.com/lightbox/view.sfly?fid=3f29910a893e77a36cbbd47cbb382743#1335578031292 Fright props 120 volt 1/2" solenoid =$60 Craftsman 5 gal air tank=$30.00 Misc. fittings=$10 (1/2" floor trap was bought at homedepot) I didn't use 1/2" brass nipples because it reduces the inside...