Usually there are a ton of times where taking advantage of deals requires you to buy an X amount of items in order to qualify for a discount price of sort. Example, buying three items to get one free or purchasing a certain amount to get free shipping.
Because of this I see a lot of people that find shopping buddies where they gather others who usually shop for the same type of items. So if such a promotion comes up the odds are that they will all want to buy something. Imagine buying $100 worth of items and getting $20 off as an example where you can easily obtain and split that discount amongst like three people.
This Christmas having a shopping buddy is definitely very beneficial since retailers are trying to wrack up sales by having many buy X amount of dollars in items and get X amount back type of bargains.