This may have been mentioned before, but Costco is a good source for free
cardboard. Today I found large sheets of corrugated cardboard, no words on
it at my local Costco. They are "throw away" items used to separate layers
of product on the pallets. Check around the toilet paper & paper towels area
to see if your Costco has these. Could be used to make small surfboards,
painted for backdrops, a base for a beach hut roof (just cover with raffia or
cut paper bags to get the thatched look), etc. Can't beat FREE!

You could also check with the local John Deere equipment dealer. Most of their parts are received in sturdy cardboard boxes. I work for one and that's where I get my cardboard.

Really any appliance stores have big boxes thank you for reminding me.

CHECK YOUR LOCAL POST OFFICE FOR CARDBAORD BOXES.JUST STOP IN AND ASK THEM IF THEY HAVE ANY CARDBAORD BOXES YOU CAN HAVE FOR VBS.EACH POST OFFICE AROUND THE COUNTRY GETS ATLEAST 4 BIG BOXES THAT ARE 4 FEET TALL EVERY NIGHT.HOPE THIS HELP EVERYONE