This is John. He is your average consumer in the typical U.S. economy.

Now just your typical consumer, John wants something right now...

A toy car perhaps?

John gazed at all the shiny toys on the shelves

in complete awe...

But he noticed his favorite model he found online was missing-all sold out!

THIS IS AN EXAMPLE OF SCARCITY.

So John decides to buy his next favorite. However, he sees two that he likes just as equally and now has to make a decision on which one to buy.

THIS IS KNOWN AS A TRADE-OFF

However, his choice forces his currently busy mom to drop her work and help him get the toy off of the high shelf.

This is because John was acting on

SELF-INTEREST

John's mother has now purchased the toy and gifted it to John. John is now the owner of the toy car.

THIS CONCEPT IS KNOWN AS PROPERTY RIGHTS