You cruise fees are just a portion of your cruise trip costs. There are a LOT of things that you can spend a lot of money on.
One item that we agree is a part of the cost of the cruise but you don't pay it up front is Gratuities (Tips) to your waitstaff (Servers, Assistant Server, Head Server) and your room Steward. The recommended tipping guide costs you $12 per night per guest. So a 7 night cruise for 3 people would work out to $12 x 7 nights x 3 people = $252. Then there are the baggage porters at the beginning and end of your cruise. Tip them a couple of bucks per bag each time.
After that all spending is Discretionary! But there are a lot of things that you can (and will want to) spend money on. Here is a very incomplete list of things you can spend money on while onboard.
Room service is free for most items on the menu (sodas and some items you have to pay for). Be sure to tip your "server" or is it runner in this case

.
DCL has reciently made it possible to tip your server on your KTTW card.
Room service There are items on the menu that Do carry a charge -soda and the other chargable beverages along with several food items.
You can purchase
snacks at Preludes (outside of the Walt Disney Theater). There is candy and popcorn to buy.
Baskets and Cruise Gifts I don't know if you can order these once you are on board but you can most definately order them before your cruise. DCL includes a brochure with your cruise documents.
Depending upon the ages of your children (or if your DW is gosh darn beautiful

)
Shutters may be a big ticket item. The 6x8 (small) photos are around $10 each. I don't remember how much the formal (large) photos are (maybe $20 each).
If you have a child that is not yet potty trained (and 3 or younger) you can "hire a babysitter" at
Flounders. You are able to initally reserve 3 time slots for your child. Later in the cruise you can see if you can get any additional times (if you need more mommy and daddy private time

) This is different than the Club, Lab or the Stack / Aloft - which are included in your cruise fees for kids from age 3 to 17.
If you stick to the
drink of the day, they will run you $4.50 each (which isn't too bad). Otherwise the prices go up from there (but still are not outrageous!!)
Speciality Drinks - like coffees, smoothies etc carry a charge. Smoothies run about $5.00 each with manditory tip.
If you buy the
wine package for dinner the cost is $185 to $250 (this info is several years old - probaby costs more now) depending upon the package purchased. If you buy
wine by the bottle I believe you can count on $50 per bottle (but if you each only drink 1 glass each, it will last for two nights and your waiters will take care of it for you!)
There is also a "
water package" that you can purchase for dinners. Why

, I don't know, the water that the ship "makes" is wonderful.
Shore excursions really add up. Even if you do a "cheep" $50 excursion that's at least $150 for a family.
If you do the
wine tasting class onboard there's a cost and I really don't know how much it is because I don't like wine that much. Same for the
Mixology and
Martini and beer tasting "classes"
Spa treatments run from $90 to well over $200 per person per treatment (count on at least $100

).
Arcade cards for the kids. Denominations start at $10 and go up from there.
Now for the
souvineers: you can get some small plastic figurine for $5. If you want a tee shirt, think at least $35, polo shirts are well over $50. A DCL frame for one of your 6x8 pictures will run you $18 to $20. Lots of fun stuff to buy for the whole family at Mickey's Mates. Then across the hall is the Treasure Ketch and that stuff is generally way more expensive!!
Then there's the "store" that's between Rock'n Bar D and Diversions on the Magic (its in the same location on the Wonder-just different Club Names) that sells
tobaco and alcohol products. I believe that any alcohol you purchase CAN NOT be consumed onboard. They will deliver it to you close to disembarkation time.
Some people have a
Bingo habit that costs them a ton of $$$$. There are 5 games played each session. There are different "pacakage" for purchase. (I have never played so I don't know the costs)
Hairbrading onboard has a per braid charge.
Landry: You’ll need money if you plan on using the Self Service Landry’s on the ship. You'll need even more money if you use the onboard Landry and Pressing service that DCL offers!
remember this is an incomplete list.
BUT ALSO REMEMBER THAT YOU DO NOT NEED TO SPEND ANY EXTRA MONEY TO HAVE A WONDERFULLY MAGICAL CRUISE!!! ::YES::
The reality is that you will spend some money while on the cruise - you will get off the ship in the ports and want to do something - even if you don't do a DCL excursion.