There's a 'sticky' (thread permanently stuck in place) at the top of the Transportation board list of topics titled something like "Popular Transportation Links". One of those links is a taxi fare estimator. Follow the instructions and you'll get an APPROXIMATE cost.
Another option is a town car.
Or, if there are three or fewer of you (and renting a car is not an option), there's the Mears shuttle. Basic information on that can be found elsewhere in the fare estimator site.