my personal goto cheapo devices are mainly little electronic components. you can get-recycle them even from old or unused devices:
- dc motors + cell phone vibrators + computer fans (adding speed controllers to them)
- piezos+ guitar coils + turntable cartridges (the worst sounding ones, the better)
- collected found objects i attach or solder inside wood-metal boxes
- old turntables with variable speed (especially with 16rpm)
you can get interesting, funny and unexpected sounds when using basic materials such as paper, plastic, metal, cardboard interacting with all these things i mentioned above.
yep, kinda koma fieldkit, but even more cheaper
keep it cheap = keep it simple. it works for me.