How do you book a cruise? First, of course, most of you book based on either the itinerary or the ship itself, then the shore excursions, dining options, onboard amenities (like the spa) and must-have lifestyle options, like children’s programs, Wi-Fi or drinks packages.

But how do you budget for that cruise? There’s the cost of the cabin, and then there’s everything else. And if you’re about to book a Carnival cruise, that budgeting has just become more challenging. It’s about to get a lot harder to predict what your real costs will be.

Welcome to the brave new world of dynamic pricing — cruise edition.