Sunvalleytek via Amazon offers the RAVPower 24-watt 2-Port USB Mini Aluminum Alloy Car Charger in Black or Red for $9.99. Coupon code "CITYEFGH" cuts the price to $7. Plus, Prime members qualify for free shipping. That's tied with our June mention, $13 off, and the lowest price we could find. This thumb-sized charger features iSmart 2.0 smart charging technology, dual 2.4-amp USB ports, multiple built-in protection methods, and an aircraft-grade aluminum alloy body.