[shiresoft]

My dad used to be a factory sales rep for different tire manufacturers over his carrier (Carlisle, Goodyear, Continental) and prices were based on quantity (e.g. how many they would commit to purchase of a particular tire and overall quantity) for a given time period (usually based upon a quarter). Some would get preferential pricing in order to "get the business" but in general there were pretty standard price sheets with a little "wiggle" room allowed for negotiations.