First, I'm almost 100% certain the Costco Visa actually nets 3% cash back for purchasing the cruise with that card as it's considered a travel purchase. If you pay less than the full amount of the cruise, I could see where it could drop that to 2%.
Second, be mindful of your onboard account if you do pre-pay your gratuities. DCL automatically adds $13.50 per person per night (they say per day, but it's easier to be sure of the correct count by totaling per night) of the sailing for gratuities. Since you will be asked to either place a minimum amount on deposit by cash or to fund with a credit card for your onboard account, these charges don't actually hit your card until the cruise ends. AND, you have the opportunity to completely remove them and tip the staff directly in cash, increase the amount, decrease the amount, etc. And, if you do wish to change the amounts (or method), you have to request that change before leaving the ship at the end of the sailing.
But, paying that with the Costco Visa should net the 3% and being an Executive Member should yield the 2% (that's 5% total) in cash-back.
Second, be mindful of your onboard account if you do pre-pay your gratuities. DCL automatically adds $13.50 per person per night (they say per day, but it's easier to be sure of the correct count by totaling per night) of the sailing for gratuities. Since you will be asked to either place a minimum amount on deposit by cash or to fund with a credit card for your onboard account, these charges don't actually hit your card until the cruise ends. AND, you have the opportunity to completely remove them and tip the staff directly in cash, increase the amount, decrease the amount, etc. And, if you do wish to change the amounts (or method), you have to request that change before leaving the ship at the end of the sailing.
No. It's only the base cruise cost that counts, before taxes & port fees.
But, paying that with the Costco Visa should net the 3% and being an Executive Member should yield the 2% (that's 5% total) in cash-back.