How can I access 2017 AGI with PLUS benefits if you're only able to pay for it when you file? 2017 was filed with a different account and I filed 2018 with this account.

Was your 2018 return in your new account also prepared in Free Edition?

Have you located the 2017 return in the old account, and when you try to download/print the PDF, does it ask you to pay?

If so, we can tell you how to start a 2018 Free Edition return in the old account just long enough to upgrade to PLUS and pay the 19.99 by credit/debit card.  You do NOT have to actually prepare and file the return.  You'll only need to fill out a little of the My Info section.  I can tell you all the steps.

Be aware there's a free option if a tax return transcript would suit your purpose.  You may be able to immediately download a 2017 return transcript at the IRS website at the link below.  If you don't qualify to open a free IRS account there, you can order one to come by postal mail, which normally takes 5-10 calendar days.   
<a rel="nofollow" target="_blank" href="http://www.irs.gov/Individuals/Get-Transcript">http://www.irs.gov/Individuals/Get-Transcript</a>

Yes, 2018 was free edition. The 2017 return is located in my other/husbands account. Says "only pay when you file" regarding PLUS benefits but I am not able to access the 2017 after I choose PLUS because I haven't paid yet. Can I somehow just pay and download the return? I tried the IRS site but its not recognizing any of my phone numbers. Very weird.

You have to sign onto the 2018 account using the exact same User ID you used to create the prior year online tax return.  Enter some personal information in the 2018 Free edition.  The program will ask if you want the Plus Upgrade.  Select the Plus Upgrade.

To pay the TurboTax online account fees by credit card so you can access your prior year online tax returns, click on Tax Tools on the left side of the online program screen.  Then click on Print Center.  Then click on Print, save or preview this year's return.  On the next page, to pay by credit card, click Pay Now.  On the next screen just click on the Continue button.  The next screen will show a review of your Fees, click on Continue.  Complete the next screen to pay by credit card and click Continue.

How to find the AGI   <a rel="nofollow" target="_blank" href="https://ttlc.intuit.com/replies/3301618">https://ttlc.intuit.com/replies/3301618</a>

Here's how to unlock access to your 2017 return.   If you haven't already started one, you must start a 2018 Free Edition return in the SAME account as the locked 2017 return.  Here are all the steps.  You may have already done some of them.  I can't tell from your statement above.  If you already upgraded to PLUS, do not upgrade any farther, or you'll have problems.

• Log in to the account that has the 2017 return, and if you haven't already started one, then start a new 2018 return in Free Edition.
  
• Answer some preliminary screens, and you will eventually come to the My Info section. At that point go to the left menu column and click on Upgrade.
  
• It may ask you to fill out a screen in the Personal Info section first.  So do that.  You can either continue completing the rest of the My Info section, if you wish, and it will eventually ask you if you want to upgrade to PLUS.  Or after filling out the first screen of personal info, you can go back to the left menu column and click Upgrade, and this time it should let you upgrade.
• NOTE:  If the PLUS option is grayed out, that means you are already in PLUS.  Do not upgrade any farther, or you'll have problems.
• So once in PLUS, you need to pay for it.
• While the return is still open, click in the left menu column on Tax Tools, then choose Print Center.
• Then choose "Print/save/preview this year's return."  (Yes, you say "this year's" since you are paying for the 2018 return to unlock the prior returns.) You won't actually have to print the 2018 return.
  
• On the next screen choose to "Pay now".
• The next screen should be an Order Summary.  Review that, and if all is OK, click Continue.
• It should then prompt you for payment by credit or debit card.  The screen only says "credit card", but it will take a debit card.
  

Thank you so much! Much appreciated.