We're getting a Minivan from MCO to the Port. When I looked into getting one for the trip back to the airport it was tripled in price. (We're going though Budget). Instead of a minivan for the trip out of the port we're getting a Grand Marque. Holds just as much luggage and 6 passengers for half the cost of a minivan. So check out all other options, you'll be surprised. (The same car out of MCO cost much more than the minivan, go figure)
Hope this made sense.
Also, check out Mousesavers.com for some discount codes.