There are some cruises leaving Charleston in September and October to Bermuda. These cruises are typical more expensive.
When you look at the breakdown of a cruise rate it isn't so much the cruise price that has changed, but taxes and fees. Carnival has a cruise in November 2012 where the breakdown has the cruise itself only $170 the rest is port charges, taxes and fees. I am thankful most of the cruise lines still have not added the fuel surcharge.