These are pretty handy. They don't work on every engine but they work most of the time. I helped a coworker the other day with the one I have jump a Honda Accord. I decided to get one for my sister to have too.

http://www.amazon.com/dp/B015KFGV52
$32.99 After Coupon OPYDQMHF
Shipping is free with prime or orders over $49.

A Rating on Fakespot [fakespot.com]

• Car Jump Starter: Jump start 5L gasoline or 3L diesel vehicle engine up to 10 times with 400 amps of peak current and heavy duty clamps and cables. 1) ECS Output 14.8V and low current to reduce heat . 2) Output 14.8V compatible with 12.8V trucks and more cars than 12V batteries.
• Advanced Multi-protection: over-current, over-voltage, over-charge, short-circuit, reverse polarity and surge protection.Over-heat protection:wait 60secs for the 3rd jump-start after 2 times continuous ignition to prevent jump starter and the battery from damaging due to high temperature condition.
• Portable Charger: 8000mAh external battery provides enough power for your usb digital devices. Output port can automatically detect the optimal charging current for your devices. Super compact design and lightweight (only 260g) ideal for carrying and storage, an excellent travel companion!
• 3-Mode LED：Flashlight, Strobe Light & SOS Signal, perfect for use in the dark.
• What You Get: 1*Kmashi Car Jump Starter Power Bank, 1*Micro USB Cable, 1*Car Start Clips, 1*User manual. 1-Year Warranty and Friendly Customer Service.