Frequently, people ask me the most reasonable way to cruise with kids. I completely identify with them since I have three children of my own which makes it quite costly to cruise. I usually tell them to look for promotions that allow kids to cruise for free. For example, Disney Cruise Lines has a current offer that covers 7-night sailings from January - March that allow children to cruise for free. For a family of 5, this can be a savings of $2400 for the family. In fact, I recently quoted a family for a January 15th sailing with the promotion and got a price of $4585. Without the promotion, the price was $7022. Truth be told, the $4585 price is the same as I got for a family of 5 for a 3-night Bahamian sailing this summer. 
What does that mean to you? Your family can now sail for 7-nights to destinations like St. Maarten and St. Thomas for the same price as 3-nights to Nassau, Bahamas.
The great thing about cruising is that all costs are included... well, within reason. The dining, the entertainment (think Disney on the ocean), the accommodations, the children's program, the taxes and port fees don't cost anything more than the price quoted.
A lot of the cruise lines are now catering to children with their entertainment. For instance, cruisers on Royal Caribbean International can cruise with Shrek and Kung Fu Panda. Norwegian Cruise Lines is offering itineraries with Sponge Bob and the gang from Nickelodeon. What kid wouldn't want to walk out to the pool and find Patrick Starfish?
Anyway, if a person can be flexible with travel dates, they can find a way to cruise with kids at a reasonable price.
