Get your taxes done using TurboTax

You are allowed to sell personal property without creating taxable income. 

You should report the 1099K income as Less Common Incom. Other Taxable Income and then report the value of the personal items as a negative reversing entry in Other Taxable Income:

You will result with two entries - 1099K Income From Sale of Personal items - and - Cost of Personal Items Reported on 1099K - one positive and one negative offsetting. each other to result in zero additional taxable income.