I see how you say cities do this but this is a new world and it's time for new less costly ways to be used. You want a ballpark this much money could have bought the land. Then you hire a man with a tractor to level the area. Then you put some cheap seats like are used at football games up. Hire someone to install a fence. Then another to sew grass seed. And Voila for less than 500000 you have a working ballpark. It may not be world class but it gets the job done and can be upgraded along and along.