DBPower's 300A Portable Car Jump Starter can jump start a 2.5L gas engine up to 20 times on a single charge. Recharging takes about five hours via USB. It can also charge devices like your phone and tablet!
VicTsing's Bluetooth FM transmitter is down to $12.99 on Amazon and includes a built-in microphone and a USB port. Anker's Roav SmartCharge transmitter is also on sale for $23.99 and includes the capability to find your car via Roav's app.