Why do I owe $50 , I thought this turbo tax was free

Your post says you're using TT Deluxe online, which is not free. Somewhere along the way they got you to respond that you wanted to switch products! And it's not easy to get back to free once you've "crossed the line" no matter how sneaky it was.

The good news, though, is if you have a simple return, it's not that hard to start over.

No you are posting from online Deluxe Live.  The "free" version of Live that you can use if you file by 2-15 is online Live Basic.   

CLEAR AND START OVER

https://ttlc.intuit.com/questions/2586254-how-do-i-clear-and-start-over

Free Edition is free only for simple returns that file a 1040 with no additional schedules, and is free as long as you don't select any add-ons or upgrades.  Click here: FREE

It is free allowing you to use our program with the navigation interview process to see what your tax refund or tax due would look like.  TurboTax is also up-to-date with the latest tax laws including the TCJA and CARE Act so you can be confident your taxes will be done right.  Once you decide to file with us, you need to pay.  The price is based on which products you are chosen after entering your information. 

If you are looking for a complete free filing, you might want to consider another option.  It's called the TaxFreedom which is an IRS Free File Program delivered by TurboTax.  It is exclusively available online and has its own dedicated website at taxfreedom.com.