My group of friends and I booked 9 rooms and we did all of the booking ourselves after checking various places (Disney's website, Travel Agents, and Costco). Costco by far had the best deal. Although it's not an immediate discount to your cruise price, you are given a Costco Cash Card after your cruise. The dollar amount varies depending on the cost of your cruise. Any one can do this. If some people in your party are not a Costco member, a Costco member can book the room for that person/family. The only difference is that your complete balance to pay the cruise is 1 month (if I recall) prior to what Disney wants. For example, my balance is due in October. If you booked it through Costco, your balance will be due in September. Check the time though as I'm not 100%. Lastly, if you have already booked through Disney, you can transfer your reservation to Costco WITHIN 30 days of purchase. You have to call Costco and get paperwork to request a change over. It has to be done within that time frame (again check dates) in order to get your Cash Card. I just saved another friend $1500 with this info. HTH