Cost of Smoothies

A juice bar sells two sizes of smoothies: small and large. A small smoothie costs $4.50, while a large smoothie costs $6.75. During a special promotion, the juice bar offers a discount where customers can buy one small smoothie and one large smoothie for a total price of $9.00. If a customer buys 3 small smoothies and 3 large smoothies without any promotions, how much will they spend in total?