I put stuff up on gumtree at a slightly optimistic price, and just wait, no rush to sell. It comes up on google or wherever and people all over the world start asking after it (months after it has sold generally). Sold a Guvnor pedal to a dude in Finland, also had a kid asking if I'd hand deliver to Cumbria, since his dad wouldn't allow a distance purchase, it was a £35 pedal.
Generally whenever I buy something at a significant price, I PM the seller asking if they are OK with Paypal, and when transaction is complete, offer the option of mutual withdrawl of sale, due to logistics issues, instead of feedback. They gave me a whole item, I want them to get the whole price.