I signed up for a Marriott credit card. After my first purchase I will get a $100 statement credit. After I get the credit card, I am going to use it to book our hotel room for the night before our cruise. The room total is $189 and we are able to leave our car there for the entire week of the cruise. So with my statement credit, it will only cost us $89.
Norwegian has a credit card rewards program. If I sign up for their card, after I spend $500, I will get 10,000 points, which is enough for $100 on board credit, and a $50 ncl gift card that we can use for the cruise. I think we will switch from using our Disney card for everything to using the ncl card to try to get as many points to turn into on board credit as we can before the cruise.
And of course, we pay the balances off every month so we don't pay interest and neither of the cards have an annual fee.