It depends. Was it a business income, hobby income or did you just sell things lying around your house such as a garage sale?
There is no one answer to the 1099-K problem. Everyone's situation is a little different. However, if you fail to enter income of any type, other than what is expressly excluded, you will hear from the IRS. A very important aspect is did you sell the item/s for a gain or a loss.
There are so many permutations to this. These are just some of the questions regarding 1099-K.
1) Some of the things I sold pertained to a business, but some did not.
You have to separate the sales that were actually business vs those that were not. You have a hybrid situation.
2) None was business income. I sold old things I had laying around the house. This is not a business. You must include the 1099-K but you can zero out the income since you had no profit.
3) I did this so it's kind of a business but not really. Yes. It's a business. Report on Schedule C.
4) I bought and resold but it was a one-off type of thing. You had a sporadic activity. It is other income.