Last July, we spent 4 days at WDW and 3 nights on the Magic. We used "Happy Limo" (recomended by mousesavers.com), and our limo costs were:
MCO to WDW Beach Club: $122
WDW Beach Club to Port C: $179
Port C to MCO: $163
They also recomended a 20% tip to the driver, so add those in as well.
Would I do it again? It was a fun "wow, we're riding in a limo" experience for my kids, but the limo from beach club to the ship smelled like a mixture of hay and manure (not strong, but enough to make us not like it), and two of the three rides we had to fiddle with the AV equipment a long while in order to get the video (kids cartoons) going.
I would have opted for a standard town car, but there were 5 of us, so we ended up taking various stretch limos.
Next time, I think we'll just try out the standard Disney supplied transportation.
We use a Private Towncar service. It's called Florida Towncar Service...The towncar holds up to 5 people.
Hmmm, maybe we'll give them a try, if a towncar can hold 5 + luggage.