We did it this July to Seez which is just out of Bourg-Saint-Maurice, toll costs were…
Out
€32.20
€41
€11
€5.20
Return
€5.20
€11
€41
€21.70
Definitely recommend driving, yes its a long day but you can take so much stuff with you like tools and spares etc.. If there are a few of you sharing the cost it works out similar to flying anyway with tolls, fuel and tunnel.
I always think you pretty much waste a whole day when flying anyway with travel to airport, wait at airport, flight and transfer the other end. We usually get an early train around 5am and get to resort for around 5pm.