I live in New England, so we thought it corny to take cruise around our own neighborhood, but we want badly to go to alaska. Prices vary widely, as do accomodations. I have checked AARP.com and AAA.com and kayak.com and its amazing to me. There are several sights like Budgettravel.com or budgetcruises.com that offer good prices. Many places will sell you a room cheaply if you are willing to book late so that they fill the rooms up. Search for last minute cruise deals, and if you are willing to leave with very little notice you can get stuff half price or lower.
Have fun, and wave if you pick New England!