How to use cigarette plug with powerpoint?

I just bought an air compressor but realized it could only be power by connecting it to the car. The plug on the end of it is the same as the one for car iPhone chargers etc. I was just wondering if anyone could give me a link to a place where i can get a transformer so i can use a powerpoint for the compressor.

Maybe one of those totable 12V packs. Auto parts retailers might have one of them.

Otherwise a 12V 5A or slightly more unregulated supply and automotive DC socket.
I couldn't say where to get one of those, apart from online vendors.