Carnival has several different tux options; the lowest price is $85.00.
google the following: "Carnival tux rental" and the first hit will be the Carnival site with a listing of their tux packages and you can download order forms and there is size info, etc. (seems like the easiest thing to do is rent one)
Hope you have a wonderful trip and enjoy.
Carnival Victory March 9, 2013
*carnival dream *
Glory 2/28/2010: Dina & Marty
Valor Feb 2009: Dina & Marty - again
Grandeur Feb 2008: DTW, Dina & Marty
Inspiration May 26, 2007
Fascination: Feb 2007
Enchantment of Seas: Sept 2006
Radiance of the Seas
Majesty of the Seas
The Big Red Boat