Related Clues:

• Onerous extra levy
• Charge less than the whole meal allowance
• Tuition, e.g
• Lawyer's percentage
• Fare add-on
• Payment to a professional
• Phone bill component
• Client's payment
• Banking charge
• Something that's charged
• It's flat when there's only one payment
• Commission, e.g
• Checking account charge
• Payment offered on a regular basis
• Mostly fodder for a mount?