Many of the smaller ones are run in conjunction with schools. That is
how the one near my college was set-up.

There was one at the University I went to, too. It was for those of us
living in campus apartments, then if nobody else wanted them, for the
public. As I recall, it was $5-$15 for the season. The soil was poor,
because people just planted and harvested instead of enriching the soil.