And the problem that the folks who are cleaning out their closets and selling used items on ebay have is, they acquired the stuff more than 7 years ago, and thus wouldn’t have receipts to show what they paid for it; they’d only have an aggregate value of what they sold the things for.
What do those folks do to show they didn’t make any profit and thus won’t owe any tax on the sales?
It probably wouldn't take much to prove it was really just an on-line garage sale, but, in most cases, I'd suggest a genuine "garage" garage sale. I know one big seller who quit because of all the "new %%##@@ rules and stuff" but i didn't ask particulars.