The price

You have already selected the company, the ship and itinerary. At this point, the choices we make from here will determine the total cost of the cruise (without "extras")

CABIN: In terms of quality, prices will rise as we move from inside (no windows) to outside (with window or porthole), and from outside category to balcony (outside cabins with a small private balcony). All cabins (not Suites) are between 10 and 16 square meters, but you don't feel of oppressed inside the cabin. Within these categories there are often sub-categories that vary by company, but following the pattern the more higher (deck), more expensive ...
Between outside and balcony there is often no price difference, but there are differences between inside an outside cabins. I prefer outside staterooms (balcony as possible), but a good friend of mine prefers to take the cheapest inside cabin, and then spend the saved money aboard, in excursions or shopping in the ports of call. He's uses the cabin for sleeping. 

MSC FANTASIA STATEROOM WITH BALCONY

WHAT IS INCLUDED IN THE PRICE: Here the policies of the companies are different, but they all follow the same pattern. You'll have to pay port taxes which are usually not included in the price (like the airport taxes), and the tricky concept called "tips". The tips have changed since the end of last century. All staff who care for you in the staterooms, restaurants receive a % of your tips. Bars and shops will change a sales commission on every drink you order, so you'll notice that they are eager to serve you a drink if they notice you have none on your table.

CABIN CREW DETAILS

Long time ago it was customary to give the tips in hand to the person in charge of ​​your stateroom, the restaurant's maître and the waiters. This way of doing things created embarrassing situaitions where money passed from hand to hand with an unfair distribution, since the money was pocketed by the chiefs and not given to the waiters.

Now all this is standardized and it's all charged in your account (some companies include the tips in the price of the cruise) and is valued at 5-6 €/$ per person per day depending on length of cruise. From there, if you want to give an extra-tip to other waiters or staff, they'll probably appreciate it, but there is no obligation. Celebrity Cruises, for example, when you order a drink, they include a "line" of extra tip on the bill, so you use it if youy want. Notice that all bar prices do not include a 15% service charge.

Turning back to the question, what is included or not, generally all food in buffet and main restaurant (the specialty restaurants are not included) is free. Talking about the drinks, there are many differences. Usually everything with self-service is free like, juice machines, coffee and tea...

Be careful, because companies like MSC opens the buffet service during breakfast, lunch and dinner, so if you want a glass of water outside these hours you'll have to pay a bottle in a bar (juice marchines are enabled only for breakfast and it is not allowed to fill bottles with water or juice). On the contrary, in U.S. companies such as Royal Caribbean the buffet is open for all day, so you can enjoy this free service of drinks all the time. 

Prices on board are expensive, but similar or cheaper than a five star hotel. Although the company policies are different, you can buy liquor outside the ship, but the cruise staff remove the bottles when you enter the ship and will return them the last day of the cruise. Sometimes they don't care about a little souvenir like a small bottle of Vinsanto, Ouzo ... There are some companies let you take two bottles of wine with you at the beginning of the cruise, but you have to drink the wine inside your stateroom. Check the terms and conditions of the company.

Other services like spa, massage etc ... have to be paid, but the daily agenda is often full of offers, and those deals will be better as you reach the end of the cruise.

CURRENCY AND PAYMENTS TO BOARD: Almost every company uses the system of "no money on board". When you get the key of your room, you have to register an account under a credit card or a prepaid amount. All purchases on board are paid with the cabin key and the day before the end of the cruise you will receive the bill. You also can check the status of your account going to guest relations at any time. Some ships like the Solstice class of Celebrity Cruises have interactive TV in the cabin where you can check the status of your bill. The currency depends on the ship. European companies set prices in euro and American companies in U.S. dollar.

EXCURSIONS: In every port of call you will have the option to go out or not. The company will offer at the beginning of the cruise a list of the excursions in your language and organized with tour operators who work with them. They are expensive but recommended in some cases. In this blog you will find a section dedicated to the most popular ports of call in Europe. There you´ll always see two options: official excursiones and cheaper alternatives proposed by me. These excursions have the advantage of going with a local guide in your language and all entrances to the places to be visited are included. Usually you´ll skip queues you go in atractions through the group entrance.

OTHER EXPENSES: Keep in mind that the cruise will always cost than you pay at the travel agency. It depends on the purchases, beverages and other services like excursions, spa... You can count with 50 to 100 €/$ per day per room, including half of excursions, drinks, tips and miscellaneous