Possibly something related to interest payments, using a car loan as an example. Show different scenarios (i.e..... for a $10,000 car, show the total cost when putting $2,000 down and financing $8,000, $5,000 and $5,000, or $8,000 and $2,000) just to give them a real world example of how much extra money they will spend by financing most of it.
Hammer home that credit cards are not a license to carry debt.
Maybe a basic overview of the financial markets (not that it's a great time to be hyping investing.... or maybe it's the best time??)