I think some answers here are wrong.
You can't deduct income you never received. You will just have less income to be taxed on. You take the loss by still deducting all your expenses but not your time or labor.
You already wrote off and expensed the shirt when you bought it. So you got a $10 Deduction. But not an extra $10. Just the original cost what (and when) you paid for it.
