Find Your Cruise
I am guessing that you are going to the Caribbean in which case you don't need to pay for any visas. Note that if your flight goes via a US airport then you will need to complete the new US ESTA application online before you go (I believe at least 3 days before but it lasts 2 years once done - please check this). You will find many web sites offering to assist with this at a charge but it is free so ignore them. For the official free version go to https://esta.cbp.dhs.gov .