Our mugs cost $11.99 at the Wilderness Lodge a couple weeks ago. You buy one for each person who wants one, and can refill them at that location as often as you want, during your stay, and during that stay only. Yes you can fill them in the morning, and go back in the afternoon to fill them. There's no limit to the amount of refills, during the stay that you bought them. You are not required to buy refillable mugs, and you only buy the amount that you want. We had one for each one of us. They more than payed for themselves. Actually I think they payed for themselves after about 6 fills. That was about our second day of the trip. They cannot be filled in the parks, but if you get your morning coffee in it, and then take it into the parks, that's not an issue. I saw plenty of that while we were down there. Some of the mugs are slightly different shapes, but I believe they are basically the same size. Some resorts may have choices for the color top or whatever, the Wilderness Lodge did not. I know that the Beach Club did though. They're really like a basic travel mug. They can be filled with coffee, hot chocolate, or soda.