One of my cars that I use for driving to and from work only has a radio in it - not even a tape player. I'm getting tired of hearing the same songs on the radio again and again, and having them be crackly during some parts of my drive. There's no audio jack on this thing, but I do have a cigarette lighter. I'm too broke right now to get a CD player - what are the cheapest alternatives these days for music listening in my situation?