20-25% of gross sales. But for shows YOU foot the accomidations and food, and figure an agreed "days pay" or something else that comps their time. Usually $200-$400 per day plus travel, and lodging is normal depending on the type of show. 3 day show $200/day, 5 day show closer to the $300 (a five day show really can trash a salesman. Especially a 10-6 show.)
A single day: set-up, show, break down $400-$500 and yes you wrap two nights of hotel around that.