there are two kinds of vendor discounts
bulk ordering discount where you get a better price per each when ordering in volume, called a sales discount and you do not book it separately, the actual cost of the items is entered.
early payment discount, you pay early like in 2/10/net 30 terms. That is your income, so on the bill enter your income account and a negative amount, then pay the balance due.
there is no actual set up for this that I am aware of
