Alert - The hottest new bugging devices are now among the least expensive. GSM SIM bugs are like cell phones, but without the keypad. Eavesdroppers call and listen from anywhere in the world.
At one time these devices sold for $250.-$500. The price has plummeted to $35.-$55. Why? The same reason their sister product (the cell phone) is often a give-away item... Economy of scale; thus proving consumer demand is fueling mass production.
Corporate Concern...
At these prices, "salting" offices with bugs becomes practical. Imagine... Buy in bulk and get custom silk screening - "Air Quality Monitor - Do Not Disturb." Even if accidentally seen, it might be accepted - "Every office has one of these."
Corporate Solution...
Periodic Eavesdropping Detection Audits are now an integral part of corporate security. Not having an eavesdropping detection program is negligence.
from a seller's web site...
"The GSM SIM Bugs are advanced audio surveillance devices. The SIM spy ear comes with compact design and embedded microphone system. This audio surveillance listening system no need software and no configuration required. Very easy to use. The only one thing you need to do is insert a pre-paid GSM SIM card into SIM card slot of the spy sim bug. Then you could hide it in an inconspicuous location and starts excellent listening surveillance." (more)
Update: The seller has stopped selling this; claiming, "Because they are incompetent." This is likely as early models did not work well, hence the big price drop. Newer models seem to be selling very well, however.