package trade {

    public class Player extends BaseEntity
    {
        public var money:int = 1000;

        public function Player() {}

    }
}

------------------------------------------

package trade {

    public class BaseEntity
    {
        private var inventory:Array = [];

        public function BaseEntity() {}

        public function buy(theItem:Item):void
        {
        }

        public function sell(theItem:Item):void
        {
        }
    }
}