Subject to subsection (b) of this section, the Board may issue to a holder of a Class D beer or Class D beer and light wine license a permit that allows the sale of beer, wine, and liquor by the drink for on–premises consumption. The permit holder: may continue to sell beer or beer and light wine for on– or off–premises consumption; but may not: sell liquor for off–premises consumption; or purchase or possess liquor on the premises in a container smaller than 23 ounces or 680 milliliters. Application for the permit may be made not less than 30 days before the day on which the permit is to take effect. Not more than 50 permits may be in existence at any one time. A license holder who is issued a permit shall receive a pro rata credit for the unexpired part of the license held when the license holder is issued the permit. The annual permit fee is $500.