$40 is the current price to prepare a federal return with TurboTax Deluxe Online (price increases later in the tax season), and will remain that price as long as you do not select any add-ons.
There is an additional price to prepare a state return. Go here to view a list of our online products. Listed under the prices you will see "State additional." Click that link to view the current price to prepare a state return for each product.
You can pay your TurboTax fees with credit card or your federal refund (if your refund is enough to cover the cost of your fees). The following TurboTax Online FAQ can provide further reference: How can I pay my TurboTax Online fees? - Community