JennyJo, if you're on Facebook then there's a on Facebook called Ozgur Eser, his page/business is Dalaman Airport Transfers.
He does shared transfers for £10 per person.
Several friends have used him, both for Dalaman and Antalya, and say he is excellent. I have just booked my husband on for when he returns from the UK on Monday evening - Ozgur will drop him in Hisaronu so I can meet him there, still for £10.
I couldn't do it any cheaper myself, with the cost of the tunnel (don't fancy the top road on my own in the dark), airport parking and diesel for our old truck.