How much it will cost to transfer visa from a private company to a private company also here in UAE?

Does anyone know how much it will cost to transfer visa from a private company to a private company also here in UAE? Is it to be paid by the employee,or the previous/current employer, or the new employer? We need to transfer visa because the previous/current employer decided to close the company. But the previous/current employer requires the staffs to pay them 5k Dhs before they will transfer the visa to the new employer. Is this right?