Selling on personal items on eBay - how to prove cost basis without a receipt?

[KarenL]

That's going to be difficult, as you know.  If you have any credit/debit card statements, that could help. 

If you received them as a gift, your basis would be $0.  If you inherited them, your cost basis would be the value on the date you received the items as inheritance.  If you purchased them yourself, that's more of a challenge.  Make every effort to try to figure out what you paid for each item at the time you purchased it, and document how you came to that amount.  Depending on the items, the internet may have sources of costs during certain years. 

Keep in mind that, without proof, the IRS would likely say it's zero for the cost of all items.