Got time for a slightly longer post now. eBay.
Seller fee offers arrive every few weeks, look in your Seller Hub or allow emails from eBay. Typically 80% off Final Value fees, for listings started between a specific Fri-Mon date range. Only on qualifying listings, but it seems to cover mine no problem. You have to click to accept the offer and activate it. (I always opt in, even though many a long weekend passes without actually getting the listings up in time.)
I only list things Buy It Now (fixed price), no offers, immediate payment required, signed for/tracked postage included. That seems to cut out a lot of hassle. Watch out for the auto relist after 30 days, as the fees offer doesn't carry over.
I include a lot of factual information (fabric, measurements, styling details etc) in the listing, and no sales puff adjectives. It minimises questions and reduces mismatch between fantasy/expectations and reality.
Toast items - new, with or without tags, or worn once briefly - sell happily at around half the original full price. They can go higher with an auction listing, but that seems to come with more mind-changers, delayed payments, and general dissatisfaction. It's taken 20 years of occasional clear outs to decide what works for me!
It is generally more rude and slapdash than it used to be. People rarely bother leaving feedback any more (hence tracked post, so I know it's arrived), and I've received items shoved in a bag with no tissue paper or note. I think that's society generally though.
I hope that's helpful to someone!