So: How much does a transfer cost to Meribel ?
For a very rough estimate until you get a journey quotation allow 100 euros per person return.
In terms of price, Chambery is normally cheapest, then Geneva, Grenoble and Lyon in that order.
Price for a private minibus for your group can depend on time of the day, the week, and the number of passengers.Also some companies will reduce the price if your journey coincides with another.
If you have 4,5,6,7,or 8 passengers then a private transfer is often cheaper than the public bus.
For groups of 1 , 2 or 3, it is better to try to do a shared transfer if possible as these are more convenient than the public bus service.
The public bus service Geneva to Meribel is quite good in the winter ski season. However the others airports do not operate such a regular service so going private is the only real option.
I hope this all helps you with your journey / travel arrangements but feel free to e-mail me if you need more help or information.