Done it every easter for the last 3 years with a minibus and 10 people. All based on from York to Tignes or Les Arcs. Van hire,diesel and euro tunnel works out at £150 to £170 per person for ten, i.e £1500 to £1700 total. 19 to 20 hour drive door to door. Its a good road trip but cheap it is not.
I know this is a snowboarders trip but it gives you an example to work from.