Yes, it is $35.00 each way per person for using Disney transportation.
Try looking into renting a car one-way, go on your cruise, and the rent another car one-way back to MCO to take ME to the resort. This may or may not come out cheaper than paying for four peole $35.00 each way.
Another option is looking at getting a car service to take you to the port and then from the port to the resort.