I got one from PayPal. The threshold is gross sales (before expenses, fees, shipping, etc.) is $5000. Under $5000: no 1099-K is sent to you or to the IRS.

How will I handle it? In a business-like fashion. I will prepare a Schedule C for my coin business and deduct expenses and the cost of goods sold. I will not ignore it, because I know that if I do I will receive a deficiency notice that will tax the entire amount and impose interest (and maybe penalties); the IRS will not (and cannot) calculate my setoffs.