A white sale is a marketing strategy in which a store steeply discounts its merchandise to increase sales during a short period of time.
In 1878, John Wanamaker of Philadelphia department store fame decreed January to be the time for a white sale. Bed linens, which were available in white only, were sold at a discount. It is believed he might have done so to keep linen makers in business during a slow time of year.
Today, white sales usually revolve around household items. However, they no longer only involve items that are white in color, and they are not restricted to take place in the month of January. Also, it is possible to have a white sale on durable goods or services.