I'll also admit to the next sentence: everybody makes sales on Christmas. The question is why not you?

So it's clear that everybody will buy different stuff for the close one on Christmas. If it's: hosting, cars, phones, audio, cd, chocolate, toys, clothes ... anything will be bought.

But the you have to consider this: the wish list is long and the budget is limited.
So any discount on the product bought will be good?

Why shouldn't you provide a sure thing?
So if you have products you will almost sale for sure on Christmas. If you have a discounted product you will sale for sure ( sale that is all ready sure ).

Do you also know when people buy for sure ( a short list ):

New Year's Day
Groundhog Day
St. Patrick's Day
Good Friday
Mother's Day
Father's Day
Independence Day
Black Friday

It's also for sure: if you don't do anything FOR SURE you won't get any of the billions spend ( for sure ) on this occasions.