Make a nearly free film slitter. Cut cheap 35mm film down to submini and 110 size. Fill those Holga and Lomo spy cameras with any type of film you want.
Especially useful for reloading Instamatics, since the film is getting hard to find. See my Pocket Instamatic
Just get a few used one-time-use cameras free at any photo lab.
I prefer the ones without a flash, but I take what I can get.ZZZZZZZZzzzZZZ ZZZTTT
The shock you get from the flash unit is molar-melting, so play it safe and get the outdoor, sunny-day, no-flash type cameras if you can.
You'll also need a pack of snap-off cutters from the dollar store, some 5 minute epoxy, a metal nut, and masking tape.