To answer Dave…
The online payment systems are subject to the same reporting requirements, but seem to be implementing them at different speeds.
Cash F2F is great, but it limits a sales market to those willing to drive.
I have used USPS money orders as a customer which are a minor inconvenience, and a mild to moderate risk. The inconvenience part is that they top out at $1K, so you may need multiples. They’re about $3 each. You buy them with cash at a Post Office clerk’s window when it’s open. It’s not a wire transfer, so you need to mail the check. You probably want some delivery insurance on the check, too.
As a seller, you’ll also need ID to cash it and probably to pick it up. The seller may want to wait for it to clear, too.
Shipping is a separate process we don’t need to cover here.
Once all that’s done there’s the possibility you (customer) get less than you’re expecting. That includes getting nothing. One advantage to using the mail is that you have some protection, but it’s slow. Mail fraud is a pretty big deal, as it’s a federal crime.
Buying via money order isn’t for the faint of heart, but it’s worked out OK for me as a buyer.