Here are just a couple things that you can do with FREE stuff from the hardware store. I included some for toddlers and a few for preschool age kiddos.
Cutting paint samples, they already have those great lines for cutting on. My daughter loves doing this! (Do not just go grab a stack from the hardware store stash, ask the manager for their outdated samples.)
We also asked the manager for the discarded keys. He gave us an entire bag and we have been having so much fun with them. I just set them out and added an empty wipe container for the toddlers to put them into.
We have also sorted them by type into tubs. So many things you can do with old keys..