You only need to report personal items that you sold if they were sold for more than what you originally paid. Let's say you purchased a vintage nut grinder for $5 in 1972 and recently sold it for $75 at a yard sale. In that case, you'd have to report the $70 profit as an investment sale.
Most of the time, personally-owned stuff like cars, appliances, clothing, furniture, and other household items decrease in value after the initial purchase. If you later sell them, it's almost always for less than what you paid, so there's no gain or loss to report. The IRS won't let you deduct losses on personal items.
However, if you have more than $600 gross payments during a calendar year for the sale of goods from a third-party settlement organization (like eBay), you'll receive a Form 1099-K reporting your sales transactions. You're still required to report your net profits from the sales as income even if you don’t receive a Form 1099-K reporting your sales.
If you sold a gift, or something that you got for free, the original purchase price is considered to be what the giver—not you—paid for it. For example, if you received a $100 espresso machine as a wedding gift and later sold it for $25, there's nothing to report. On the other hand, if you sold your espresso machine for $250, you'd report the $150 profit as an investment sale ($250 selling price minus the $100 purchase price paid by the giver).