Please see this answer from MaryK1.
If you sold items on ebay, but not as a business or with the intention of making money, you would not have to report the income on your tax return- unless you sold the items for more than you purchased them for. Even though you do not have to report the income, keep a copy of the 1099-K with a list of the items you sold and how much, with your tax records.
From the Massachusetts Department of Revenue: If you receive either a federal Form 1099-K or a Massachusetts Form M-1099-K that shows amounts paid to you, you must report taxable amounts on Schedule X, as other income, or if such amounts are derived from a trade or business, on Schedule C. See TIR 17-XX. (emphasis added)
