Even though cruise travel is one of your best vacation buys and consistently rated highly by travelers, there are some things to put in perspective. I suggest that you take port lectures by cruise staff lightly. They are to designed to promote shore excursions, which can be terrific but cost extra. You can often have a great time on your own. You can get pretty thirsty out on deck and it is amazing how these tabs run up.
Some lines even charge for soft drinks with meals.
And please do not be intimidated by the ever-present shipboard photographer. Now on to the bargains. To get the deepest discounts, your best bet is a cruise discounter. These are the folks the cruise lines go to, confident that their volume will help fill remaining cabins. The cruise lines don't have to spend money to advertise and consumers get a deal.