It sounds like you might have a balance due on your federal or state taxes, which is what is prompting the request for payment since you are in our Free Edition product. Or, did you add PLUS benefits to your Free Edition product?
If you are being asked for a credit card info in Easy Extension, it may be because you added a TurboTax product (to do your taxes later) on a previous screen. The credit card is needed to pay for that product — not the extension. If you would like to remove the product, go back to the product selection page and click "I'll choose later" at the bottom of the screen.