So if a stallion bids on a mare to discount his breeding fee, the mare owner pays him
So Stallion owner bids on mare to discount his fee, she accepts -> she pays him directly

But

Stallion owner bids on mare to discount her fee, he is buying from her -> he pays mare owner. So she accepts the offer, and then he gets a pay now and she pays him. 

Makes sense? 


There are 2 scenarios, one were we are inviting the person to accept our offer for their goods (we want to purchase their goods/ we send them money), and one where we want to sell our goods (we want them to buy our goods/they send us money)
