Most charge about $70 one way, and about $120 or so round trip. But, that is for a towncar. A limo should cost more. For instance, FL Tours, a board sponsor, charges $129 r/t for a towncar, and $230 for a limo. Other companies are in the same ball park.
Mark with Tiffany Towncars has an exec towncar that is huge and it was the same price as a regular towncar. He was awesome. Limos are just way more expensive. DH and I only use Tiffany we never take DME and DH probably wont ever take DME--he wants the serive directly to the door.
Be careful some of the limos want xx amount for a minimum of xx hours--which adds on to the regular cost at times.
The towncar companies also provide SUVs and Vans if needed for about $20 more than a towncar.