Bolton Valley isn't a huge place, but the walk-up rate for a full-day, midweek ticket is $69. They also have variable pricing if you want to buy in advance....at the moment, I'm seeing prices for as low as $39.
And if you really want to ski a lot, Bolton is one of the few places that has night skiing. So you can ski from 9am - 10pm if you really need to work off those Christmas Calories.