The short form, 1040EZ, was discontinued by the IRS in tax year 2018: https://www.investopedia.com/terms/1/1040ez.asp You've probably been filing the 1040 through TurboTax free edition and didn't know it.
TurboTax Free edition, from their website:
Those filing in TurboTax Free Edition, TurboTax Live Assisted Basic or TurboTax Live Full Service Basic will be able to file a limited IRS Schedule 1 if they have hobby income or personal property rental income reported on a Form 1099-K, and/or a limited IRS Schedule D if they have personal item sales income reported on Form 1099-K.
If you want to document your net income from selling those personal items and don't have an exact record of every shoe you purchased, you can look up your transaction history on ebay (or wherever you sold it) and then just google the shoe you sold: "Nike Airmax" "MSRP"
You have zero net income, zero profit, from your ebay revenue. You pay no additional taxes on this net income.