Polaroid Cameras.

They were very popular when I was younger as we could take "naughty pictures" without having to get the film processed.

In 6th form, however, some students were doing photography courses so had access to a darkroom and processing equipment. They had a nice little sideline in processing films that we wouldn't want processed elsewhere. Or course, eventually they were found out and about two dozen of us were lined up for six of the best.