Well, a "junk camera" is hard to define, then... Let's see, how about a "Time" camera, all-plastic 35mm promotional give-away to new subscribers to Time magazine? It does work.
How about a "Yumeka"? Another plastic 35 which even came with headphones for listening to its built-in AM radio between -or maybe during- snaps. Still boxed, haven't run a roll through this one.
Junk... or eBay treasures? 😉