I filed my extension on Turbotax. Do I have to pay for Turbotax Online before the 4/15 deadline if I want to use it to file later?

Filing a tax extension with TurboTax is free.

 

You can get an extension:

You must have a TurboTax account, or create one.

1. Click on the website  Free federal tax extension is now available 
2. Select [File Now]
3. Log into your account
4. Your screen will show Get started on your federal extension
5. Follow the interview

Also see   States That Accept Federal Extension

 

Thank you but your response doesn't address my question. 

"I was wondering if I need to pay for it (pay for Turbo Tax online) before the 4/15 deadline if I want to use Turbotax Online to calculate and file my taxes by the Oct. 15 extension deadline?"

and to clarify why i'm asking. I heard that if we don't pay for Turbotax Online by a certain date, we'll get locked out of using it and would have to use some offline version. 

you won't be able to file after Oct 15 the six-month extension deadline.

you heard correctly. Support should give you the desktop program to continue if you did already pay.

Your computer must be compatible.