This is one of my favorite projects to date and you don't need much for it! I bought one sheet of 4ft x 8ft 1/2" plywood for $35. Now, keep in mind- I made really large half moons and I made 12 of these. You can made them any scale you want and as many as you want! I didn't even end up using all of the plywood, either!
You do need to have some kind of tool to cut the wood into semi-circles. I used a jigsaw. I ended up buying these fine finish blades to make a really clean cut!