Wal-Mart, Target, Bed Bath and Beyond, eBay and Amazon.com all have numerous brands and styles of cup heaters for sale. Popular manufacturer brands are available including Mr. Coffee, Toastmaster, Wagan, Roadpro and Disney.
Various heating styles available, include hot plate style where the cup sits on the heater, heated sleeves that surround the cup, entire cups that are heaters and immersion units that clip to the side with a heating element reaching into the liquid. Several power supply options are available, such as 110v, battery, 12v DC for autos and USB for use with laptops. Many of the USB models come with additional ports for connecting multiple devices.