No, you do not have to pay taxes on personal items sold at a loss. You don't need the exact cost basis because personal losses aren't deductible. Poshmark likely has sent or will send a 1099-K.
Here is how to report this in TurboTax Online:
- Within your tax return go to the magnifying glass icon on the top right, type 1099-K and select the Jump to 1099-K link in the search results
- Choose Add a 1099-K
- The next screen will ask "Which type of income your 1099-K is for?" choose Personal item sales, then Continue
- Enter the information from your 1099-K
- After you choose continue, the next screen will show "Personal Item Sales". Here is where you choose "All items were sold at a loss or had no gain"
This answer has been verified for accuracy by an Intuit expert employee
