Okay, try this:
1) Up at the top of your window is a link that says "Search". Click on it.
2) A little window will pop up. Try typing in something like "Keystone discount lift tickets", or maybe even just "discount lift tickets".
3) Be rewarded with a couple years worth of people's experiences.
I'd suggest stopping at a grocery store - most sell discounted tickets ($5 - $10 off). There may be discounts that are better at the ticket window if you purchase a multiday pass. The Summit Daily newspaper will have info about that, and you can get the newspaper at the grocery store. Those promotions change on a weekly basis, so it's hard to say if they'll be any good. Copper is doing a big event next weekend (Gravity Games), so maybe Keystone will counter with some cheap ticket prices.