Our car is old enough to contain a radio/cassette player, which is only
annoying when we depart on a pilgrimage 500 miles down south, and would
like to play mp3s.

What we need is something cheap n cheerful, ideally to play mp3s from a
phone, USB stick or possibly SD card. Something that can be run or
charged from the car cigarette lighter.

Just seen eBay item 291474623251 which plugs into the cigarette lighter
and plays from SD card. I think it also plays from a phone. I'm not
sure how it works, but I think the idea is the output is picked up by
the car radio, and plays through the usual car speakers.

Have I understood correctly? Any other suggestions? It didn't occur to
me that I could get something that would play through the car speakers,
so was looking at mini boom boxes.

--
Graeme