I built one as follows.

10x10 sq

2x10 joist and end caps
2x6 decking
blue plastic drums ( I got free but they are about 6$ each to buy
nylon rope
1-1/2 galvanized electrical conduit
2 inch galvanized u-straps for conduit

I have provided a crude pic below. Basically I spaced the floor joist so that the drums would wedge them selfs in between and not touch the floor decking putting the load on the joist. Rope was only needed in case of high wind, otherwise they stay in place with out it. all put together with decking screws



The road goes on forever and the party nevers end...............................................