Now that your cruise is booked, you are probably going to need airplane tickets to get to and from the city where the cruise will be departing.
Most cruise ships depart from major cities which are serviced by a wide variety of airlines.
Next to the actual cruise tickets, airplane tickets are normally the next biggest expense of taking a cruise. Instead of just accepting the prices quoted by the airlines, you should spend some time searching for cheaper airplane tickets.
With a little bit of effort, you can normally save $100 or more.
I am certain taht you will be able to find something much more entertaining to spend the money on during your cruise.

