1) eBay reports aggregate sales >$600 to the I.R.S. 2) Most items sold on eBay are sold for less than they were purchased (i.e., anything used), so the likeliho

1) eBay reports aggregate sales >$600 to the I.R.S. 2) Most items sold on eBay are sold for less than they were purchased (i.e., anything used), so the likelihood of recognizing gain on any sale is low. No gain recognition = no taxes incurred. 3) Sale of items above (your) purchase price do incur taxable income. If you do not report such income, your tax year never closes. That means there is no deadline as to when the IRS can go after you for penalties and back interest. 4) Sales tax is collected by the seller on behalf of the buyer. You mean "use taxes", which are paid by the buyer himself.