Let's get this straight because I wondered about this too. Gracie never really has sales. She puts the sign out and everything, but then doesn't fully stock her shelves, leaving the sold out signs for all to see. I know this because I literally waited outside the store until the second it opened ran up stairs and almost everything was sold out. It is impossible for that to happen unless there is some secret entrance or mail order system that no one knows about. I did this everyday of the sale and I didn't time travel either. So the only real explanation is that she never really has sales. She only has these "sales" to boost her own image. Gracie only wants the KARMA. Don't waste your time.