i'm also curious about this. does the structure/content of the waiver signed by users have anything to do with insurance costs? what about training for employees? do incidents such as noobs dropping people while lowering or the occasional compound fracture in the bouldering area affect insurance costs? or just if someone actually brings a civil suit for damages...?
I own enclosureclimbing.com. Busy gym with 700 members and 150 average checkins per day. Our insurance is around $8000 per year. The price is based on revenue. Your #1 cost will be staffing, and expect it to be 1/3-1/2 of your revenue. Insurance, while expensive, is not a significant expense.