Fat Kid Tax

When Government tries to promote healthy choice by adjusting the price of public school lunches so that getting two lunches is more expensive, rather than making schools serve more filling and nutritious lunches.

I'm SOOO hungry but I can't get another lunch because I don't have money to pay the fat kid tax.

Kid Tax

The price of the extra things you buy in a store because you happen to have your kids in tow.

Kid: Hey, those keychains are cool!
...
Cashier (@ checkout): Those keychains are $4.99
Parent: Well, there's another $5 Kid Tax!