Personal sales at a loss do not need to be reported, as they are nondeductible personal losses. They cannot offset capital gains, either. You have a loss if your sales price is less than you paid for the personal item. Unreimbursed shipping costs also reduce your gain. So you only need to report items that have increased in value on your tax return. You can report them on Schedule D if you do not have a 1099-K. See the IRS website at www.irs.gov/taxtopics/tc409?form=MG0AV3 for further discussion.
