So here's how I made mine:
I went to home Depot and bought a board. I had them cut one 5 foot piece and two 9 inch pieces.
Then I bought four of these things? I don't know what they are called but they are with the roofing stuff:) I screwed the two nine inch piece to either end using the "thingies" and I was done! The whole thing cost me like five bucks!
This is Caden the first day I made it. Daddy had to help but now he walks it like a pro! He also drives his cars on it!