Less
Bulk quantities should cost less per unit than smaller quantities (~as the retailer should benefit from lower transaction costs per unit).
Stores’ own-brand products should cost less per unit than name-brand products (~as the retailer’s general brand should cost less than the name-brand).
More
Units of a product offered in convenient places may cost more than the same product inconvenient locations (~as the retailer may have higher costs connected with that location’s convenience).
Price salience.