You can check out travelocity.com or orbitz.com to book a Canadian cruise and get various deals and specials. Depending on the time you want to travel you can find very affordable packages.
The Jamica Cruise is a good cheap cruise package. You have the Mexico Cruise, Puerto Rico Cruise, Bahama's Curise and there are many other cruises that are inexpensive as well.
I would recommend trying a website like Kayak or Travelocity to find your perfect vacation package! They can offer some great deals and help you find what you're looking for for your vacation!