Most sale signs in grocery stores are red, which psychologically tricks consumers into believing that it's a special, limited-time price. However, this isn't necessarily the case.
Many Big Box retailers offer those same items at the sale price most, if not all, of the time. The red tag only makes consumers think that they're getting a better price.
Sometimes, to trick people even further, retail outlets jack up the price in the weeks prior to the promo to make the sale price seem like a total bargain by comparison.