If you think that fuel is expensive in the USA, take a trip to Europe and do some driving there.
To make an even better comparison rent a full size car over there with automatic transmission and all the options. Then figure out the rental price, the fuel and add the lodging plus food and then tell that you can't afford to vacation over here.
Carnival Liberty New Year's Eve 2007
Liberty of the Seas 5/2008+11/2009
Allure 1/16/ 2011
Vision OTS 2-14-2015
Freedom OTS 3/6/16