5. Electricity Usage Monitor - Price: $24.99
Time Until Break Even: 3 years
With this device, you can see how much of a phantom load your powered-down electrical devices are still pulling through the wall outlet. If you discover devices that are pulling a significant load, unplugging them (or using an appropriate device to stop the drain) will save you money over time. This device is also useful for figuring out how much power various home devices are draining and, with some quick calculations, exactly how much it’s costing you.