[SOLVED] Stirling Engine Information

[StirlingEngine]

Just want to make sure everyone is aware that the Stirling engine is advancing and has many great applications in power/energy generation, cooling, and water purification.

http://www.StirlingInfo.com has current news, and an organized directory.

[Funlar]

Does anyone know where to buy a cheap Stirling engine that will be used for a classroom presentation? I tried eBay but they are selling anywhere between $130 - $300, and thats way more than I want to spend for a 5 min one time presentation.
Thanks