TechRabbit offers the Insite Bluetooth Smart Proximity Alarm, model no. LBL811, for $2.99 with free shipping. That's the lowest total price we could find by $4. (For further comparison, it's also tied with our mention from three weeks ago for a refurb; this one is new.) Designed to alert you when your smartphone or valuables wander out of range, it can be configured to ring your device, send alerts, or transmit coordinates for its last location. The receiver also has a keychain and storage for your credit cards.