The Cards:
Action Cards may be played to initiate the action printed on the card or may be used as money of the value noted in the upper left and lower right corners.
Property Cards some denote a specific property and some are wild. They show property name, set to which they belong (or in which sets they may be used), rental costs, number of properties in their set and their value when used to make payments.
House/Hotel Cards may be used to increase the rental cost of a property set. They also have a monetary value for use in making payments.
Money Cards are used to make payments.