DBRoth via Amazon offers the Duracell 175-watt DC to AC Pocket Power Inverter with USB Port, model no. DRINVP175, for $39.99. Coupon code "YFT4INX7" cuts it to $27.99. With free shipping, that's tied with our October mention as the lowest total price we've seen. (It's also a current price low by $12.) This device connects to a 12-volt car outlet to convert it into a 120-volt AC outlet and is able to simultaneously run and recharge both an AC and USB device.