I don't know where you are getting your information from, but I can tell you it's not a good source. You can go to a website of any cruise line and see what the prices are for the port you want to sail out of. The best price will be for an inside cabin on a lower deck. You'll pay more for an outside cabin, and even more for a balcony cabin. Usually prices are higher from April through August, and during the Holidays. There is no easy way to get upgrades - they seem to be pretty rare. You might want to talk to a travel agent that specializes in cruises.