It's usually a wicker basket of seasonal food and drink, which you can pay for during the rest of the year to ease the expense of having to stock up at Christmas.
Seems to me to be an expensive way of doing it. Much better to get a large cardboard box and drop unperishable items in there bit by bit as they become available.
I suppose, if you want to give a hamper as a present, it would look a bit better in a wicker basked but there's other ways of getting round that.