I made these tiedowns with about $20 worth of materials. They hold well in most types of soil, and it is easy to pull the stakes out one-at-a-time when it's time to leave.

My latest ones use 2" dia. aluminum tube 1/4" wall, and 3/8 SS rod for the stakes. A hardware store eyebolt with nylock nut on the bottom completes the tiedown. The holes for the stakes are at 90 degrees to each other.