The early discounted prices usually expire on March 1 and go up to full price. See the online prices here. You can pay early and file later to lock in the early price.
Online Prices
https://turbotax.intuit.com/personal-taxes/online/
How to review your fees
https://ttlc.intuit.com/community/charges-and-fees/help/how-do-i-review-my-fees-in-turbotax-online/0...
How to pay, use this FAQ on how to preview your return. It will make you pay if you say you want to print now.
https://ttlc.intuit.com/questions/1901539-how-do-i-preview-my-turbotax-online-return-before-filing
