Amazon offers Prime members the CyberPower Dual USB Power Station, model no. PS205U, for $14.99 with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $6.83.) That's the lowest total price we could find by $3. It features two 2.1-amp USB ports, two 3-prong 120-volt outlets, and a device cradle.