To get the Reverb 1099, it’s gross sales, not profit. And it’s not per sale, it’s cumulative over the entire year. And while you may not pay any tax depending upon your basis, it’s another reason for the IRS to eye each of us suspiciously.
And to brighten your day, most current homeowners policies state that a hobby generating $2,000 gross sales (cumulative) is considered a “business.” Business is excluded under both property and liability sections of homeowners policies (with few exceptions). Good luck with your “TV insurance companies,” especially.