Bens Bus operate cheap shared transfers throughout the winter ski season from just over £82 Return. From Geneva Airport they go direct to the Meribel valley resorts. From Geneva, Grenoble and Lyon Airports they also stop at Moutiers bus station, the transport hub for all the 3 valleys ski resorts. Public buses run  regularly from Moutiers up to Meribel and the other 3 valleys resorts. Cost last time we checked was about 15 Euros per person to Meribel or Mottaret and about 80 euros for a private taxi for 4 people from the bus station up to resort. For full details, prices and timetable visit the Bens Bus website.