You should stop to buy stamps at noon because that's the only time they're being sold at wholesale price. Everyone's so busy eating and working and being at school, that they miss this awesome deal, but not you. Everyday at noon you stock up on wholesale stamps. Do you send a lot of mail? No, you probably just collect them. But they were cheap, so who cares!
Oh, one more thing. Going at noon isn't enough, you have to say the password to get them at wholesale price too. The password is "Oh Roshi" (おろし). Okay, so maybe that's just the name of the guy there, but it always works when I want to get stamps wholesale so you should do it too!