Where are you going? There are sticky topics at the top of several forums with details of airport transfers such as Shuttle Direct and Resorthoppa.

luci

Fuerteventura - San Jorge Hotel

I see there isn't an airport transfers topic in the Fuertaventura forum, but if you check some of the Costas forums such as the Costa Blanca you will find the names of transfers companies. Most of them operate all over Europe and you can check the priced on their sites.

http://www.shuttledirect.com
http://www.resorthoppa.com

are two to try.

luci

Although these europe-wide companies probably provide a reasonable service they seem very expensive.
A private transfer from a local company in Turunc, Turkey to and from Dalaman airport for the coming season costs approx £85 to £90 return for up to 4 people. The price quoted on Shuttle Direct was £223.
I think a taxi from the airport taxi rank may even be cheaper, not sure of the prices this season but a taxi from the airport taxi rank was £75 one way for 4 people a couple of years ago.
I know on the Turkey forum on this website people will always be able to help with names of local companies for transfers, so if you can find one that way on other forums it will probably be cheaper.