I know that theres a barn in alberta called Spruce Meadows. They charge like over 1,000 but they have AMAZING facilities. Like pre-olympic stuff. So really unless you have a huge indoor and outdoor arena and several other arenas for specific disciplines with amazing stalls, feeding, huge paddocks and pastures and like a gazilion other amazing amenities, you probably shouldn't be charging over 500 for board. That's kind of the average for box stall board around here, 400-500. One place I know charges 500 for a box stall. They have a huge outdoor arena, huge indoor, 90 acre cross country course and 600+ acres of trails that they own.