This right here is what is so ****ed up. YOU have to PROVE you didnt make money selling YOUR **** that YOU already paid THEM taxes on. Buncha no good lying pieces of smegma dog ****.It doesnt matter if you are selling your stuff on here, or on any platform as long as you are not making a profit. If you sell a $1000 item, (watch, golf club, gun, sofa, car, whatever) for equal to or less than you paid for it, the IRS cannot tax you. If you sell it for $1100, they can tax you on the $100 profit you made on it.
The pain in the ass is going to be receipts for all the old crap you decide to sell. Or maybe the IRS will give us a pass like they did with obama care fines and not require documentation.
If you are selling stuff on ebay or etsy, you should have some cost basis, and you can claim that as non-taxable. Again, you will probably need receipts, ie pain in the ass.