Deductions & credits

IRS form 1099-B flows to IRS form 8949.  IRS form 8949 flows to Schedule D Capital Gains and Losses.

The items may be lumped together but I would report two categories:

1. personal items sold for less than their basis, and 
2. personal items sold for more than their basis.

Personal items sold for less than their basis (most likely, the original purchase price) report $0 capital gain on line 7 of the Federal 1040 tax return.

Personal items sold for more than their basis report the gain on line 7 of the Federal 1040 tax return.  See this example.

                             Selling           Cost

                              Price             Basis

Couch                    $500              $2,000        Capital loss on personal item = $0 loss

Jewelry                  $400               $300           Capital gain on personal item = $100 gain

Chair                     $100               $100            No capital gain or loss

                               $1,000           $2,400

Any loss on the personal items are reported as $0 and the losses may not offset the gains on the personal items.

@Mikster2023