Since I received a 1099-K (and the IRS / state also received it), I was under the assumption I had to attach it to my tax return "just because". I'm in a $600 state, which is why I still received it this year.
Last time I received/filed a 1099-K, I did file it under 1040-C "self employed". I was selling alot of stuff on ebay back then. It was in my PayPal account and mixed together with a bunch of Ibotta grocery rebates. I ended up paying income tax on that too, because H&R said I had to. H&R was absolutely horrible.
