“Teach about checking accounts, credit cards. Teach about why payday loans suck. Explain how credit works.”
Explaining how it works is meaningless to teenagers.
They need concrete lessons such as being forced to spend a Saturday doing demeaning boring work. On Monday, they are handed 70 dollars for their labors. Then they should have to stand in line to file past a series of tables manned by representative government agencies. At the first table, for example, the IRS takes away 20 percent, the next table, FICA, etc. Be sure to include representative property, school, and other taxes.
When they are done they will be holding twenty or so dollars for their efforts. Declare they are wealthy and take another ten percent from them for the common good. Then take the money confiscated from them and buy pizza for another class.
Of course, to be fair, offer to let them buy their own from what they have left.
Cheers!