TigerDirect offers the Ultra USB 2.0 Keylogger, model no. U12-41374, for $29.99 plus $2.29 for shipping. That's $10 under our July mention and the lowest total price we could find. This device is purportedly undetectable by software and monitors all text-based activities on a computer. It features 2MB of on-board memory and can store up to six months worth of data.