I’m in Orkney, nearest music shops are Inverness or Aberdeen i.e the locality where the OP is.
If I am looking for a bass, I browse BC, the Gallery, Bass Bros or Bass Direct, all of whom deliver here unless I’m ordering something silly like an Ampeg 8x10.
Some local folk here have seriously good kit, but it rarely gets sold, though if it does a bargain can be had because folk don’t want to post. We have our own local FB for sales which works okay though selection is limited. It is what it is.
Outside of that local group I don’t look at FB marketplace owing to potential scams.