The Home Depot, Amazon.com, Wal-Mart, Sears and Best Buy are some stores that sell alternating current to direct current electrical power converters. There are a wide range of prices and functionality available depending on the specific use.
Many of the available converters change 120-volt AC to 12-volt DC and supply one standard automobile accessory style plug with which to connect devices. Some larger converters supply multiple output connection options to power different types of DC devices.
Most of the retailers also sell power inverters that perform the opposite function. Inverters plug into a vehicle's accessory port and convert the DC power to AC, giving users one or more standard home electrical outlets and allowing them to use 120-volt AC devices on the road.