Lend
You substitute some shellfish for collateral so your friend will lend you some money. Normally he would ask for something more valuable, but you’ve convinced him to substitute these shellfish for what he would normally take as collateral when lending to people.
"Shellfish used to be money! People used to lend them to each other all the time!" you say to your friend. "Hmm... okay, I guess so," they say skeptically.
たい
か
None
You want your friend to lend you some money so you can buy yourself a car (か). You need money and a car a lot more than you need this pile of shellfish, so you’re happy to put them up as collateral for the loan.
Imagine yourself in this new car that you got with the money your friend lent you. Hear the roar of the engine and feel the wind in your hair.