It’s not just the shipping costs or taxes that people are concerned about.
Many don’t realize this, but carriers (at least UPS) will only insure for damage if “they” box the item up themselves. Even if i box the speakers or any other item in its original container, all insurance covers is a loss by the carrier.
So that 2K pair of speakers I insure for 2K and box up myself and ship gets damaged in transit? I eat the cost of the repair or loss of value to the new owner or have to pay to have it shipped back. I could end up losing shipping costs x 2 plus the actual money I got for the sold item.
That’s why shipping sucks so hard and folks are willing to take less money (normally) for a local sale, regardless of payment type.