Record each transaction

Keep purchase cost, sale amount, fees, shipping, refunds and dates. Retain receipts and the basis for allocating costs to bundles. Reconcile platform reports with bank deposits so that fees and withheld amounts are not mistaken for missing revenue or counted twice.

Understand the classification question

Selling personal possessions and buying inventory for profit can have different tax treatment. A platform reporting form is not itself a complete calculation of taxable profit or a statement that no other income must be reported. Review current IRS guidance for your facts and tax year.

Do not guess on deductions

Business expenses, inventory accounting and losses can have specific rules. Personal use, mixed-use items and missing purchase records complicate the analysis. A profit calculator is not a tax return. Ask a qualified tax professional about uncertain records or classification before filing.

Check other obligations

Sales-tax collection, permits and local business requirements depend on activity and jurisdiction. A marketplace's collection service may not cover every sale or obligation. Keep buyer information private and retain only what is necessary for records and compliance. Consult the relevant official state or local authority.

Before you act

  • Write down the assumptions that would change this decision.
  • Confirm current requirements with the relevant official source or a qualified professional.
  • Keep sensitive documents out of public links and unknown forms.

Primary sources & further reading

Editorial review: November 2026. Sources are background guidance, not endorsements of this site. Check current local requirements.