Buy is related to Exchange. Sell is a type of Exchange. you would Sell because Money. Money is related to Rent. 
Horse is related to Stable. you are likely to find Hay in/at/on Stable. Hay is related to Dried. Dried is a form of Dry. 
Buy <--RelatedTo--> Exchange <--IsA-- Sell --MotivatedByGoal--> Money <--RelatedTo--> Rent 
Horse <--RelatedTo--> Stable <--AtLocation-- Hay <--RelatedTo--> Dried --FormOf--> Dry 