Carnival has offered lots of good deals for single cruisers in Caribbean and South America areas. I've been on Carnival 6x (going on 7 in a week) by myself and I love it. I've paid a little extra but got my own room, that way I would not have to worry about who my roommate would be in case we are not getting along. I am sure you don't want to ruin your vacation. So, check out Carnival cruise line.