selling items

You would report them as a sale of an asset, like a stock.

In TurboTax Online, you can enter the sale of personal items by following these steps:

1. Open your tax return
2. Click on Federal in the left-hand column,
3. Then on Wages & Income
4. choose Investments and Savings and click on the down arrow on the right
5. Click on Stocks, Cryptocurrency, Mutual Funds, Bonds, Other (1099-B)
6. Did you sell any investments?
   1. yes
7. Did you receive a form 1099-B or brokerage statement? 
   1. No
8. Select Other (other investment purpose) from the list of investments.
9. Follow the TurboTax interview to enter your information.
   1. If you incur sale expenses, you can subtract them from the proceeds.