Fyi fees for most Xmas markets are about 500 per day, plus power at 200 per day, plus staff, vans, accommodation if needed, stock costs, insurance etc, then VAT and tax on anything left. They have to overcharge but sadly we all have less and less disposable ourselves. Seen it from both sides and it's soul destroying to have people ridicule you for charging what you need to charge.
Just a general observation here, not necessarily applicable.