Is there a way to pay for 2017 upgrade in order to obtain a .tax file?

@ marshal-agregado 

Yes, we can tell you specific steps to do that once we understand your situation and what all you have done.  So I need to ask you some questions.

Why are you wanting the *.tax2017 data file?   Are you needing to amend a 2017 online return in the complimentary 2017 "amend software?"

You may have a problem, however.  You appear to be using Online Premier; at least that is what is displayed underneath your question above.    How did you end up in Premier?  Is Premier what you used to prepare your 2018 return, or did you upgrade too far trying to get the 2017 return?   The minimum upgrade to unlock a 2017 return is PLUS at 19.99.   Premier, however, is 79.99 for Federal return and 44.99 for any state return, if applicable.

Have you already filed a 2018 online return using TurboTax?   And is your 2018 return in the same account as the 2017 return?

We can tell you your options when you answer the questions above.   You "may" be able to downgrade if you have not already filed the 2018 return (we can tell you the steps).  If you have already filed the 2018 return, however, and then upgraded to Premier by mistake, we can tell you how to phone TurboTax Support to ask them to unlock the 2017 return so you can download the PDF and *.tax2017 data file.  They may not even charge you.

There's also a free option if a return transcript will suit your purpose.   You may be able to immediately download one at the IRS website if you qualify to open an IRS account there.  Otherwise, to order a transcript to come by postal mail takes 5-10 calendar days.
http://www.irs.gov/Individuals/Get-Transcript