We just returned from the 4 night cruise/3 day land last Sunday. What an awesome trip!!! The drinks work like this:
When you board the ship and they usher you to the dining rooms for lunch, there are stations set up with hundreds of these mugs. They are sold for $20 (on the 4 niter) plus an extra $2 if you buy one with a lanyard strap attached. The strap is pretty much useless unless your cup is empty because the sipper hole does not close. The cups come in 3 different colors - red, blue and yellow. You can fill these cups unlimited times from places all over the ship with soft drinks, lemonade, fruit punch, unsweetened iced tea, water, hot tea, coffee and hot chocolate.
The place where we filled our mugs was at the beverage station on Deck 9 near the Mickey Pool. That beverage station also has paper cups with covers. Every drink at that station is free all the time -- and it has all of the above drinks minus the soft drinks. So, we used our $20 drink mugs to drink free lemonade and free iced tea. Plus, we had to carry the darn things around and clean them.
If we were to do it again, we would not purchase the mugs, because the weather was so hot that the soda (carbonation) was not the best thing for us to drink. The lemonade and punch was great for the kids, and we drank quite a bit of the iced tea.
On occasion, we would have soda with our meals -- as soft drinks are included with meals, along with all of the other drinks.
Ironically, we continued our vacation at the Wilderness Lodge, where we purchased 2 of their $11 mugs. It was well worth the money there to do that -- and the covers were sealable, so there was minimal dripping when we carried them around.