The short answer is yes. When you sell items you make yourself that is typically a business activity and it reportable to the IRS no matter how you are paid. Keep in mind you will also have business expenses for materials etc.
This article is very helpful in knowing how to report this income to the IRS. https://turbotax.intuit.com/tax-tips/self-employment-taxes/-what-is-a-schedule-c-irs-form/L7v0iDelI
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If a 1099-K is, you have to deal with this on your tax return, but the 1099-K by itself does not mean the money is taxable. It depends on what you did to get the money.
You might be selling as a business or a hobby. Since one of the key factors for treating your income as business income is the desire to make a profit, selling old items for less than their purchase price is not a business for tax purposes. However, if you mix selling old and new items for profit, then you have a business, and the answer below does not apply and you do need to report a business.
Selling tangible personal property is a capital transaction reported on form 8489 and schedule D. If you sell for more than your cost basis, you have a capital gain. If you sell for less than your basis, you have a capital loss. However, capital losses on personal property are not deductible and do not offset your gains. So if you sell 10 items with a combined loss of $1000 and one item with a gain of $10, you have a $10 capital gain.
You need a spreadsheet listing your items with a description, date purchased, cost when new, date sold, and selling price. If you don't have receipts, make your best guess and hope you aren't audited. Without proof of your cost, the IRS would be allowed to disallow your costs and declare the entire proceeds as taxable income. A listing made at the time of sale is better than nothing, but not as good as receipts. The more complete and businesslike your records, the more the likely auditor is to cut you some slack if some of your items are less-well documented. Keeping your listings may help as well, if you are listing items as used, that will help to establish they were your previously purchased used items.
On your tax return, there are two ways of dealing with the 1099-K. There may be a new procedure for 2022 since so many more people will be getting 1099-K forms, we don't know yet. These are the old procedures.
1. Leave the 1099-K off your return. Report your sales as capital transactions on schedule D. File by mail and include a written explanation of why you left off the 1099-K.
2. Enter the 1099-K as "other income." Then create a negative item of other income to offset the 1099-k. Enter your sales as capital transactions, and e-file. The IRS may as later for an explanation of the negative item, you would reply with a letter of explanation and a copy of your records.