High school is a time to prepare your child for the (da da da-da!) “REAL WORLD”. One of the things he will need to know is how to handle his finances; this includes earning money, saving money, paying bills, and balancing a checkbook. Of course, he will also need to know how to write checks, track debit card purchases and use the register.
I am working on getting resources in our free homeschooling downloads page for money resources! In the meantime, you can check out Money Instructor. This site has everything you can possibly need to teach your high schooler how to manage their checkbook.
In addition to the lessons on checks, they have Basic Money Skills, Saving & Investing, Earning & Spending and more. I highly recommend you check this site out for aids in teaching your teen about managing money.