Only if you make money, so if you buy for $1,000 and sell for $600 you don't pay taxes.
But PayPal reports it on the 1099K either way so you will have to itemize it on your return or the IRS will assume that's $1000 in income as opposed to a $400 loss. PayPal won't know the cost basis of the item.
Not a big deal, just more paperwork and time for the little guy.