My family doesn't celebrate that, but we do like to go out for a bit durning christmas eve and eat some nice chinese food!!!! I love christmas for that reason, lol!!! For me christmas eve is chinese food day I love chinese food! I'd say we don't spend a lot on that meal.
I just did my budget yesterday, which I thought it wasn't that bad considering there were only three of us in my family. I would probably spend about $80 or some on Christmas dinner, which I will bring my parents to go out to eat.
In Japan, there's a weird tradition of eating KFC (yes, Kentucky Fried Chicken) as the Christmas meal. I'll pass.
But there are also these things called "enkai" which are basically parties with coworkers. My school usually has one after special events (culture festival, end of semester, sports day), so I might go if there's one for winter break. They're expensive, though, at 5000 yen (50 USD) per person.