If you want to hire Madonna to perform at your event, that will run you $1M. At least. Hugh McIntyre writes at Forbes:
Just the other day, Priceonomics published a leaked list of a range of how much bands and singers earn per performance, with the numbers ranging from $1,000 to six digits. While the list may not be perfect, the numbers are close to what an appearance would fetch. The firm that leaked the list, Degy Entertainment, is known for college shows, which can cost a premium, much as someone hiring a celebrity for a private party would know. These numbers are pre-expense, so if you’re thinking of snatching up some of these stars for your next event, think about adding a hefty sum onto these numbers for flights, hotel, etc. Sorry to put the damper on you hiring Ellie Goulding for your birthday.
Priceonomics has gigantic list with hundreds of acts and their per night fees.