Look south and west, not at the Tarentaise. The famous names of the Three Valleys and the Espace Killy are world class and priced accordingly. The real savings sit in the Southern Alps around Vars, Risoul, Serre Chevalier and Praloup, and in the Pyrenees at Saint Lary Soulan, Cauterets and Peyragudes, where lift passes routinely cost half as much and a week's apartment rent is a different conversation entirely.
Lodging is where a budget is won or lost, not lift tickets. Book a self catering apartment at the foot of the slopes, cook most nights, and drive rather than fly into the nearest small airport. A ski in ski out apartment in Risoul plus a supermarket shop will undercut a catered week almost anywhere, and the school holiday weeks are the single biggest price multiplier to avoid.
Decide what you are buying before you book. If you want sheer mileage for the money, Serre Chevalier wins. If you want the lowest possible total cost, the Pyrenees win. Strong skiers chasing cheap powder should read our France powder ranking, families can compare the wider region in our budget Alps guide and the neighbours in budget Austria, and the full picture lives in the France destination guide.