Something small for us to start,
We recycled the wooden pallet our cart was originally delivered on and created the frame, painted in weather proof paint so it lasts. Then we also took a menu board that was out for scrap (as the wooden frame it was in was rotten) and used the black board out of it.
This was the result after a bit of elbow greese: Its a 100% recycled A board. It cost us nothing to create.