Where to purchase dozens (or hundreds) of old cell phones / tablets?

4 years ago from , The BHW Group

Ive got an idea to do an installation for the front wall of my agency and it would requires dozens/hundreds of old smart phones/tablets. All they'd need to be able to do is turn on. People re/upcycle their phones all the time. Was curious if there were any places that were selling these phones in volume?