I see multiple entries where the price of the hay is listed as 0 but comments ask that callers inquire about the price - e.g. [1]. Is there some percentage of

I see multiple entries where the price of the hay is listed as 0 but comments ask that callers inquire about the price - e.g. [1]. Is there some percentage of price that posters are charged by the exchange that they are trying to avoid, or is this because price changes in a complex way depending on quantity? 1 - http://www.hayexchange.com/display_detail_hay.php?id=294517 http://www.hayexchange.com/display_detail_hay.php?id=294517