That really depends on your personnal habits and what you like to do. The cost of the cruise does cover all meals in the main dining room and the Lido buffet. The Miracle has a reservation only dining room Nick & Nora's, which if you choose to dine there, has a cover charge. I believe $25pp. The speciality coffee, soft drinks, and alcohol drinks are extra and a 15% gratuity will be added to the bill. You will pay for things you choose to do of personnal nature such as the spa, bingo, casino, shore excursions, gift shop. The gymnasium is free, however; there are certain classes such as yoga, pilates, there is a nominal fee. All your entertainment of production shows, comedians, magicians, music in lounges, poolside entertainment is free. The ship will charge your onboard account $10 per person per day for gratuites to cover your cabin steward, waiter, asst waiter, and buffet staff. You may adjust the gratuites. Up or down. The staff works very hard and long hours.
You may charge anything ship related to your on board account so you would need cash for casino, bingo, and for things in port such as taxis, souvenirs, perhaps lunch and drinks. Depending on your spending habits. Take lots of ones and smaller bills. There is a safe in your room to lock up valuables and excess cash. Only take ashore an estimate of what you think you might need. You can use your charge cards in the reputable jewelry stores for large purchases. IE; Diamonds International, Tanzanite Intl. Columbian Emeralds. The ship will have a port talk to recommend stores. While many believe the ship gets a kick back from the recommended stores, it also is wise to use these stores because they are more reputable. Also if you have a problem with a piece of jewelry within 30 days of purchase the cruise line will take care of it for you. If you buy in a small mom&pop shady store you are on your own.