Found theese on a website called Electronic Goldmine, they cost $2.50 a pop and are actually quite nice in my opinion. They operate on 120 volts AC and are quite loud considering their size. They are suprisingly robust for their cost. I personally like them.
Here is a link to the webpage that has them.
http://www.goldmine-elec-products.com/prodinfo.asp?number=G16776