Unless you have some inside contacts, the cost of doing concrete or asphalt for that matter is very expensive. In addition, you are putting it on someone else's property and you can't take it with you if he doesn't want you there sometime in the future. You may want to look into a geotextile like petromat which is cheaper, removeable and repairable. It's not as nice as concrete or asphalt but you can roll it up and put it somewhere else if you lose your field. JMO.

Marty