It is free to “file”the federal return. File means either submit electronicly or get a printed paper return to mail in. They charge for preparing the return which you should get discounted and there is a charge to file the state return and any other extras you purchase Audit protection etc.
Did you follow the link directly from the Uber app or from an email sent to you by Uber? Otherwise I doubt it will recognize or allow you to input a discount code in later on. I successfully got the same discount you were going for by signing in via the TurboTax offer found within the app. You should only need to pay for state tax filing. Cost should amount to around $50.
ShiK is free now regardless of link or not.... they do a terrible job at letting you know, but when you get to the end when it’s time to pay, it will show zero due (fed and state), and I used the self employed version too.