The pricing is a little over the original plan, but the idea behind it is the same as any market, you pay the organiser, not to use "public" property, but to be under their organisation, and an endorsed part of the event. It prevents chaos, frankly, allowing buyers to easily browse stalls and find what they want (IC).
Other than that, remember the rules on griefing/trolling, trying to bring someone's idea down IC because OOC you think it isn't right, well that isn't right.