I've just got back from doing the Overland Track (great fun!), flying into Launceston and thought I would share my experience in arranging transport to the start. We had a booking though tiger wildernesss - $300. I found them difficult to deal with, and in the end they stuffed our booking up and thought we were arriving a day later than we were! With no transport we approached a taxi and negotiated a flat rate deal which was actually cheaper.
So for everyone's reference, you can negotiate a taxi fare between $250 - $300. The meter on our taxi went to $330 (not much more than what Tiger Wilderness charges), but we paid $280.
It's still a rip-off when I compare the level of service and price you get in NZ for the same thing. There's room for another operator to come in and do a proper job!