I don't have a website for you but.........We just borrowed some from another school for our carnival and are looking at building some for our own school. They are 8 feet across the front and 4 feet down each side forming a 2 ft tall U shape. They are attached at the corners with hinges so they can fold down for storage. It would take a full sheet of plywood for each booth. the front and sides are framed with 2 x 4's. They had them painted different colors. They really added a more defined and professional look to our carnival. Hope this helps you. We are checking to see if this could be used as an Eagle scout project since they could get a lot of the items donated. My husband said it would cost around $25.00 per booth if you pay for all of the materials.
Our school has had a great carnival for years. We have booths made of PVC pipe. They are basically cubes that are 8' x 8' x 8' or 10' x 10' x 10'. You connect the corners with PVC 3-way joints I think. Each booth has a colorful sheet that we decorate and hang on the back. If you really wanted to dress it up you could make a little valence that would go across the top front. The PVC pipe is relatively inexpensive, lightweight, easy to store, and durable.