Erin’s Dad is right.
Run the Net Price Calculator.
Does your child have a NCP? If so, is that person cooperative and has agreed to pay fair share?
Does any parent/stepparent take any business deductions? Even if you don’t own a business, you could be taking substantial business deductions. Realtors often deduct all sort so things, including cars, gas, cell phones, copy services, etc.
Do you own a business? Does it have assets?
Do you own property with lots of equity and/or do you own properties other than your own home?