Those looking for an exciting vacation might find cruises advertised recently for under $400 per person, but it is easy to be fooled by the tempting prices.

On the one hand, cruises can be a solid budget option. With lodging, meals, activities, and a pre-determined itinerary often included in the cruise package, cruises can offer great value for the purchase.

However, cruise executives often overinflate the value of a cruise: pay one price, and your lodging, food, entertainment, and visits to multiple ports are included. In truth, there are many hidden or unexpected costs in a cruise experience that can rack up the charges for an unseasoned vacationer, especially when it comes to dry land experiences.

When travelers hear the term “all-inclusive,” most probably think that everything is paid for in one swipe. In reality, an “all-inclusive” trip really only applies to high-priced luxury cruises. Most other cruise experiences, especially on big-ship lines like Carnival, Royal Caribbean, and Norwegian, involve hidden fees.

Recently, several cruise lines have increased automatic gratuity, Wi-Fi prices, and room service delivery surcharges. Some of the charges are unavoidable, such as gratuity, but most are discretionary add-ons that customers are not anticipating.

Even travelers hoping to save by bringing their own bottles of champagne and wine will likely face fees, usually ranging from $10 to $30, if they wish to drink outside of their rooms. This is similar to Texas corkage fees. Otherwise, drinking onboard could get a little pricey.

Seemingly insignificant items such as cocktails, Wi-Fi, or spa treatments might be outside of the initial fare and wind up costing unforeseen amounts.

Port visits can surprise travelers with the extra costs, such as cruise-sponsored excursions that can cost anywhere from $30 to $600 a person.

Ted Blank, a travel advisor affiliated with Travel Leaders, said that he does his best to prepare clients for these surprises.

“And then I say, ‘But it’s important to understand that cruising isn’t an all-inclusive vacation unless you get to really the luxury level of cruising,’” Blank told The Washington Post. “Many things are included in the price, but you need to kind of plan for and budget for additional costs that you’ll incur in the course of the vacation.”

For some travelers, there is no need to go beyond the basics included in the cruise fare. Many activities on board a cruise ship are free, such as the pool, using the gym, or sometimes miniature golf. But other activities cost extra, such as exercise classes, arcades, or go-kart rides. These can be avoided by the thrifty vacationer.

To anyone thinking about going on a cruise, plan your own excursions and decide exactly what you want to spend your time and money on in order to get the most out of your trip.

But most importantly, do your research to understand what is covered in the initial fare and what will cost extra.