Can I say I'm a full-time student to avoid receiving the Retirement Savings Contribution credit and thus avoid paying for TurboTax deluxe? I'm not a student.

Yes, that will disqualify you for the Retirement Savings Credit and shouldn't impact the rest of your return.

Yes---you can trick the software into disqualifying you for that credit by saying you were a student if you want to avoid paying the upgrade for the software.  That information does not go to the IRS--it just lets you avoid the upgrade to a paid version.

Or.....you could keep the credit and use other software.

Use this IRS site for other ways to file for free.  There are 8  free software versions available from the IRS Free File site

https://apps.irs.gov/app/freeFile/

Or—if you live in certain states you may be eligible to use the new IRS Direct File

( AZ, CA, FL, MA, NH, NV, NY, SD, TN, TX, WA, WY )

https://directfile.irs.gov/