Cruising is one of the best vacation values going. The all-inclusive fare includes accommodations, meals and entertainment. But did you know that cruise lines get most of their revenue from the things passengers buy aboard ship? Yep. That’s why they aggressively peddle their photos, spa services, art auctions, shore excursions, jewelry, casino and drinks of the day.

Do you really need that faux-gold-by-the-inch jewelry or another souvenir cocktail glass? If you’re not careful, you can easily spend more for onboard extras than you did on the cruise fare. The key to avoiding a bank-breaking bill is knowing what to expect.

Tipping. Except on a few luxury cruise ships, which have no tipping required policies, you are expected to tip your cabin steward, dining room waiter and assistant waiter. Don’t fight it. These crew members work very hard for low wages, and your tips are necessary to their livelihood. Many lines recommend that each passenger tip about $10 per day, as follows: cabin steward, $3.50; dining room waiter and assistant waiter, $5.50 (shared); bistro service waiter and cooks, $1. Bar bills are automatically charged a 15 percent gratuity for the bartender. Special service personnel such as the maitre ‘d, deck stewards and bellmen should be tipped as service is rendered; for other crew tips, payment at the end of the cruise is customary.

Airport transfers. The cost of a round-trip airport transfer purchased through the cruise line is often $40 per person or more. A better (and often faster) way to get to and from the ship is by local taxi. The fare is usually around $20, and the cab will take up to four people.

Photo opps. It starts before you even set foot on the ship, with the obligatory pose by the S.S. Life Preserver. Ship photographers are everywhere — in the dining room, on the pool deck, in the showroom. You’ll feel like you are being stalked by paparazzi before you sit down to your first dinner. But here’s the thing: You don’t have to have your picture taken and you don’t have to buy any photo taken of you. Considering that prices range from $15 to $30 for each picture, you can certainly save a lot of money by bringing your own camera and asking fellow passengers to snap photos for you. On the other hand, professional portraits do make nice souvenirs, especially when you’re all gussied up for the formal night of the cruise.

Art auctions. Shipboard art auctions can be a lot of fun, and they do offer free champagne and that’s the problem. If you’re not careful with the cheap bubbly, you could end up owning a picture that resembles four dogs playing poker. I’ve seen this happen a number of times, and I’ve seen the remorseful bidder go home hundreds of dollars poorer. If you see something you really like, take a picture of it and see if a local art gallery can find it or something like it for you. You usually get better art deals on land, where you can play the competition among art galleries.

Bar bill. Soft drinks, bottled water and alcoholic drinks can really add up. These refreshments are seldom included in the cruise fare, except on luxury cruises, so you have to think ahead. Find out if your ship offers a soda package — a deal that offers unlimited sodas for $20 to $35, a real boon for people traveling with kids. Cruise lines prefer that you buy alcoholic drinks directly from them, but you can bring your own wine aboard to be served to you at dinner. The catch is that you will be charged a corkage fee usually around $10 per bottle. (Do not try to bring bottles of liquor aboard; the cruise line will confiscate them, though they will return them to you at the end of the cruise; however, you might get away with a flask.) One of the easiest ways to save beverage money is to bring a water bottle or coffee mug on board and fill it up in the self-serve buffet. Instead of plopping down $2 for a bottle of water, I fill up a few of my own.

Specialty restaurants. Many mainstream and premium cruise lines now have onboard alternative restaurants, which offer specialty menus with prices ranging from $10 to $45 per person. Sure, the food is interesting, but is it any better than what’s served in the ship’s dining room for free? It depends on your taste and what the cruise line is offering. For example, Norwegian Cruise Line’s “Freestyle Cruising” plan offers a variety of excellent alternative dining choices, including an amazing teppanyaki table experience at a reasonable cost of $20.

Internet access. Most ships have Internet access, but they often charge an outrageous per-minute fee. Some cruise lines offer package deals for a fixed fee, usually around $100 for 250 minutes of Internet access. You can save a lot of money by visiting an Internet facility in port. Ask a crew member where to find an Internet cafe on shore, or check out the local public library, where you can sometimes check your e-mail for free.

Gambling. Shipboard casinos are getting bigger and bigger, which means that more and more money is being lost at sea. If you decide to roll the dice, set a limit on how much you are willing to risk, then leave as soon as you lose it.

Spa services. While pampering should be part of every cruise vacation, frequenting the ship’s spa can be costly. A massage can range anywhere from $80 to $180 per hour not to mention the 18 percent tip. You can save money on spa treatments by looking for discounted spa specials, which are usually offered when the ship is in port. Keep in mind that the spa staff works on commission; this means you will often get a sales pitch for their products after your treatments. Unless you really like the products, don’t feel obliged to purchase them. Many shipboard spas feature products by Steiner Leisure. If you like them, check out the prices on TimeToSpa.com; you can often get a better deal there than on the ship.

Shore excursions. Shore excursions can be pricey, especially on such destination-intensive itineraries as Alaska, Europe and Hawaii. In most cases, it’s easy to arrange your own excursions and save money. Visit the port’s official tourism Web site for up-to-date information on tour operators and pricing. You can find a comprehensive list of worldwide tourism sites at JohnnyJet.com.

Companies that specialize in planning tours for cruise passengers include Port Promotions and Shore Trips. Both allow you to book your shore excursions before you leave home, and the savings can be significant. For example, Port Promotions offers an Alaska package of three excursions in Skagway, Juneau and Ketchikan (one excursion in each port) for $123 per person. If you are going to Alaska or Seattle, try to get your hands on The Great Alaskan TourSaver and Seattle TourSaver. Both books offer coupons for free admissions, two-for-one tours, flight-seeing, whale watching, free car rentals, second night free hotels and much more.

Despite the cost, there is one very good reason to purchase your shore excursions through the cruise line: If your excursion runs late, the ship will not leave port without you. Anytime you schedule an independent trip, you lose that safety net, so be sure to leave enough time to get back to the ship before departure because, believe me, the ship will leave without you.

Laundry. Laundry and dry cleaning charges on a cruise can be exorbitant. For example, a T-shirt can cost $4 to wash and a pair of underwear $2. Check to see if there is a self-service launderette. That will be much cheaper typically $3 to $5 per load. If you don’t feel like doing your own laundry and need some clean clothes, don’t despair. Most cruise lines set aside one day on each voyage when they will wash a bag of laundry for a set fee, usually $10 to $15 per bag (the cruise line provides the bag).

Film and sundries. Buy plenty of film and other camera supplies at home, because once on board, the price doubles. For example, the $20 underwater camera I bought on my last cruise would have cost me $10 at Target. The same can be said for pain relievers, sunscreen and many other small, personal-use items.

Don’t get me wrong, I am not advocating spending nothing aboard ship, just that you stay the course within your allotted budget. If you don’t, your next hard-earned cruise vacation could be at risk.

Sound off! Do you have a comment, an idea, a complaint or a problem for Anita to solve? Send her an e-mail and you might find yourself in her next column.