Form 1099K for Sales of Personal Items

It sounds like you are reporting Personal item sales.  In TurboTax Online, to report Personal item sales of $0, follow these directions.  

• Down the left side of the screen, click on Tax Home.
• Click on the down arrow to the right of Review.
• Click on the blue band labeled Review.
• Down the left side of the screen, click Federal.
• Down the left side of the screen, click Wages & Income.
• Scroll down to Other Common Income click on the dropdown menu.
• Click Start/Revisit to the right of Form 1099-K.
• At the screen Did you get a 1099-K?, select Yes.
• At the screen How would you like to upload your 1099-K? click Type it in myself. 
• At the screen Which type of income is your 1099-K for, select the button for Personal item sales.  Click Continue.
• At the screen Let's get the info from your 1099-K, enter the information.     
• Click Continue.
• At the screen Personal Item Sales, select All items were sold at a loss or had no gain.  Click Continue.

The entire amount of the IRS form 1099-K will be reported on Schedule 1 Form 1040 as included in error or for personal items sold at a loss.