Now, all of my shopping emails never hit my inbox. They immediately get filtered into a shopping folder (I call it "Shopping," but you might go with "Stay out of here" or "You don't need any of this"), where they wait for me to realize I need a new white t-shirt or something to hang in my hallway. Then, I click in and see if any of my favorite retailers are having sales. If not, I wait. They always come around eventually.
I briefly spoke about Gmail filters in number 059 of my 100 Tech Tips. This is a great way to keep your inbox cleaner and avoid numerous distracting interrupting you every day.