You
should make a "good faith effort" to ascertain the Fair
Market Value (FMV) of the personal items you sell at a profit (for more than you originally paid for it). Do you
know what a similar item may be worth? E.g., a 32" TV is about $150
at a big-box store.
Please read this TurboTax FAQ for more information about selling personal items: https://ttlc.intuit.com/replies/3995054
Please read this TurboTax FAQ for more information about how
to report investment sales: https://ttlc.intuit.com/replies/4790340
Unless... you sell items online as a business. Then you would report this income, expenses, etc., on a Schedule C.
To enter/edit Schedule
C (self-employment):
1. Open your return (or continue if open).
2. Type “schedule c”
(upper-case works too) in Search box (upper right-hand corner of the screen)
3. Click on “Jump to schedule
c” link.
4. Answer screen interview prompts.
