Carnival Dream/New Orleans Port

Depends on how many in your group, and how close to boarding/departure your flight arrives. Google is your best bet to find links and phone numbers to do the proper math.

Taxi to the port is $36 for one or two people, $15 per person for more than two. So actually unless you by yourself taxi is cheaper. Also I understand Lyft is approved and can be much cheaper and there is some kind of special when you sign up for Lyft.

Here this may help

http://www.neworleanscruisetips.com/transportation-options-to-the-new-orleans-cruise-port/