I have a pre purchased turbo tax filing kit from a retail store. How do I insert it to pay for turbo tax ?

You cannot use that license code to pay for online TurboTax software.  That code is only for the CD/download.   

We see people get confused and they keep logging in to online software which will require them to pay at the end.   You need to use the desktop software.   One way to tell if you are using the right software---your tool bar.   Online software has the toolbar in a black vertical column on the left side of the screen.   Desktop software has the tools up on the top of your TT screen.

You appear to be posting from online software instead of the desktop CD/download software that the license code is for.  If you are using online, you are using the wrong program.  You need to switch to the desktop software to get what you paid for.  You have to download it, update it and open it up from your own hard drive to use it.  

https://ttlc.intuit.com/community/choosing-a-product/help/how-do-i-switch-from-turbotax-online-to-the-turbotax-software/00/26129