The best (and really the only) way to get lift tickets for Park City Mountain is through the Epic Pass:
https://www.epicpass.com/
Epic offers several pass options — full season passes, local passes, multi-day options, and excellent military discounts. The earlier you buy, the better the price, so we highly recommend purchasing as soon as possible.
Park City Mountain does not sell discounted day tickets at the window, and there are no third-party discount options. Buying early through Epic Pass is the only way to save.