Hi Nita69, thanks for the question.
Regardless if you receive a 1099-K from eBay, you are selling products/goods. If the activity is continuous and on-going, you should report the gross sales amounts on Schedule C, Profit or Loss from Business. The cost basis should be similar to the sales price since it is the fair market value with an unrelated 3rd party in an open sales platform. Your Schedule C should break even/small loss/small profit.
If the activity is a hobby (no profit motive), then you need to report the income as is. Cost basis can only be deducted if you itemize deductions on Schedule A. With today's high standard deductions, hobby expenses/costs are usually not deducted on Schedule A.
Hope the above helps.
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