Baldwin5-welcome to cruise chat!
You will find that many people here are or may be travel agents, and, through work, cruise alot more than people like you and I who do take almost a whole year to save up and pay for our cruises. Don't feel wierd for having to budget expenses-many of us are in the same boat.
Now, our first 7 day cruise to the Eastern Caribbean, being very careful with money, we spent about $900 extra (we do NOT drink, so that saved us much). The typical trinkets you'd buy on any vacation should be expected on a cruise. Almost every port you stop at will have locals trying to sell you almost anything, some forcefully. If you know the word "NO", you'll do fine.
On board, photos are taken all over the ship of you and others, and are available to buy somewhere on the ship in the camera shop. There are many on board shops too, where ytou can shop and buy things, some expensive, and other things VERY expensive! Tips can be pre-paid (there are basic prices that RCCL asks for it's crew-your travel agent or RCCL's travel planners can explain them. For a standard 7 day cruise, the basic tip expense for two people is $136.50. Travel insurance is a very good idea, and is $118.00 for two. (These are our expenses for a 7 day Mariner cruise in September this year.)You can also spend money in the casino-how much is up to you. There is a "drug store" type shop on the ship with basic medications,etc.
For your first cruise, I'm a big fan of paying for your shore excursions through RCCL. They may be a bit more expensive than a port vendor(not THAT much), but you ARE guarenteed that the ship will NOT leave without you if something happens on your outting, and they are late to get back to the ship. Our first Captain, Iask Olsen, stressed the need to be back in time, lest you become a new resident of whichever island you were visiting that day.
We like to book our cruise a year in advance with a standard $500 deposit for two ($250. each), and then pay $250. per month until the trip is paid. This way doesn't make it SEEM so expensive.
I'm sure there are other costs I haven't thought of, and other people will inform you of them here.
Enjoy yourself! You're going to LOVE crusing, and I can almost bet you'll be hooked like the rest of us here!