Cheap Cell Phone Jammer
Only $166. It’s the size of a cell phone, has a 5-10 meter range, and blocks GSM 850, 900, 1800, and 1900 MHz.
I want one.
Pity they’re illegal to use in the U.S.:
In the United States, United Kingdom, Australia and many other countries, blocking cell-phone services (as well as any other electronic transmissions) is against the law. In the United States, cell-phone jamming is covered under the Communications Act of 1934, which prohibits people from “willfully or maliciously interfering with the radio communications of any station licensed or authorized” to operate. In fact, the “manufacture, importation, sale or offer for sale, including advertising, of devices designed to block or jam wireless transmissions is prohibited” as well.
EDITED TO ADD (10/12): Here’s an even cheaper model. I’ve been told that Deal Extreme ships the unit with a label that says it’s a LED flashlight—with a value of HKD 45—so it will just slip through customs.
EDITED TO ADD (11/6): A video demo.