Bottle caps and bottles
Kitchen towel rolls
Cereal box or any other kind of packing material
Use anything you have at home (thats the whole idea)
I covered a few big boxes with white paper and helped my son(Aarav) tape a few pieces together. What started as a car quickly turned into a robot, with a little imagination and lot of glue Aarav was ready to color his robot. Soon the robot had a name..Mr.Memorybot. Aarav took his time to color it with his fingers and paint brush.
It was hours of fun, you can never go wrong with glue, color and boxes(give it a try)
Start a conversation of what you are trying to make, before you start joining the pieces, get the kid(s) excited.
Go with the flow, let them use their imagination
Make it fun, add color or sparkles like their favorite color.