you would Buy because Thing. Person does not want (to) Thing. Person does not want (to) Slip. 
Laughter is related to Play. Play is related to Rent. Rent is related to Money. Money is the opposite of Debt. 
Buy --MotivatedByGoal--> Thing <--NotDesires-- Person --NotDesires--> Slip 
Laughter <--RelatedTo--> Play <--RelatedTo--> Rent <--RelatedTo--> Money <--Antonym--> Debt 