Or say you own a pharmacy or a nail salon or a gas station or a pizza shop and you want to add a new item, change a price, announce a contest or start a new delivery service.
There may be a life-size polar bear in a cowboy hat and hula skirt standing in front of a tourist shop that makes for memorable souvenir photos, and one could argue that any item is for sale if you make the right offer, but if it isn't specifically there to be sold, it doesn't count.