Its not that hard to set up a part time business, and the benefits outweigh the effort. The business would pay the expenses involved with the sales, and that could end up reducing your overall taxable income.

Get hooked up with a good accountant and they can tell you what can legally be written off as expenses, and what is considered income. Then, when you get the Ebay form, you tell your accountant that "That is covered in my "income" section".

The next thing is, who cares what you paid for something 20 years ago? The government only wants to see a receipt that says you paid $$$ for something and see what you sold it for. You can buy receipt books pretty cheap. Its not hard to find an old receipt for something you may have bought last year and sold this year, for a profit or a loss. A receipt from Joe's Garage Sale for 'this item' for this 'amount' of cash is all you need. Its not your problem to remember where "Joe's Garage Sale" place was, you have the receipt for the part you sold. If the receipt from Joe's wasn't in your hand writing, it would probably be better.