$100

€28.5

"UnPlugged is an application to notify when the power cord of the Mac is unplugged or plugged in. Notifications are done using Growl, or with a Alertwindow, when Growl is not installed. This app is done with Cocoa and doesn't use as much RAM and CPU usage as the other tools available."

"MiniBatteryLogger monitors your laptop’s battery, traces the graph of charge and amperage over time, compares your battery with other users, logs relevant power events and alerts you with Growl notifications."

"MiniBatteryStatus is a small Dashboard widget that monitors battery status, charge percentage and remaining battery life. Integrated with Growl to alert you when it's time to recharge your battery."