For last-minute adventure seekers or those who love a good deal, Holland America Line has introduced a unique Standby List Program, offering travelers the chance to cruise for as little as $49 a day. The concept is simple: Travelers add their names to a standby list for a specific itinerary, and if unsold rooms become available, they’ll be notified two to seven days before departure.

Although the program offers huge savings, it also has a few catches. Standby passengers do not have control over their stateroom category, must be ready to embark on short notice and must be prepared for the possibility of not being selected (in which case they’ll receive a full refund). Young families are also excluded, because the fares are available only to those 21 and older.

“Travelers who want to benefit from a standby fare should keep in mind that once confirmed, Holland America Line assigns their room,” Rob Clabbers, founder and president of the agency Q Cruise + Travel, told Condé Nast Traveler. “While that might result in savings, it means travelers may end up in the last remaining and likely less preferred location — above a theater or night club (or) all the way forward or aft. While this may work for some, it is definitely not recommended for those who fear seasickness, have mobility issues, would like to be close to travel companions, (or) want to be near or away from elevators,” he said.

However, the payoff could be significant for those willing to roll the dice, especially for group travelers. The third and fourth guests in a stateroom can sail almost for free, paying only taxes and fees.

Despite the uncertainties, the allure of deeply discounted fares and the excitement of a last-minute adventure may be enough to entice daring travelers. As one Reddit user put it, “I feel like (a) 7-day notice for going to Hawaii is the kind of anxiety I need in my life.”

Cruise ships participating in the Standby List Program depart from Seattle; Whittier, Alaska; San Diego; Boston; Ft. Lauderdale, Florida; Montreal; Quebec; and Vancouver, Canada.

For those willing to embrace the unpredictability and short notice, Holland America’s program offers a unique opportunity to experience the joys of cruising at a fraction of the usual cost. It’s a gamble, but for the right traveler, it just might pay off.