Ring of Charisma reduces the price of all shops. While equipped, shops that charge gold (including secret shops such as the Glass Shop, Food Shop, Shriner, Transmogrifier, and Conjurer) have their costs reduced by 50% (rounded up), Blood Shop costs are reduced by 2 HP (but not below 0.5 HP), and the Pawnbroker buys items for their full CoinCost instead of the usual 50%.
While generally weaker compared to alternative ring options, Ring of Charisma still has occasional powerful applications. Be on the lookout for Ring of Charisma being sold alongside more expensive items, such as Heavy Plate, to make shopping sprees a little easier on the wallet. An early Ring of Charisma find can make otherwise deadly Blood Shop transactions easily affordable. If using a Conjurer for a ring and Ring of Charisma is produced, make sure to wear it for any additional conjures.