Mine is nothing more than the already hard sandy soil smoothed out a bit. Steel mesh (like they put in concrete floors) weighed down and dragged behind a 4x4 works well. We'll see how it goes when the rains come - first year here...
That's how mine started. It gets better every year. It takes everything from Ultralights to Light Twins and Air Tractors/Droms with full loads. I would use it whilst it had water laying on it if I needed to. It's 1000m+ long and I'd say it cost me less than $200 to make. It's 8 years since it was put there.