It’s such a difficult balance. People like to bargain. I set some items at the lowest possible price I could take and switch off offers on those items (any lower and it wouldn’t be worth the time & fuel to get to the Post Office!), but people then make offers or ask for an even lower price in the messages, on items which are clearly already at a bargain basement price for fantastic quality, high original retail, and most often never used. So I tend to leave prices marginally higher (but never high - I’m always losing money!) to allow for offers. There’s no action which bulletproofs you against people who want something for a mad price. I take both approaches and neither is perfect, as I know you’ve experienced too. I keep promising myself I’ll stop selling but there’s always something that makes me think, “Oh, just this last thing, then!”
Nope, seriously, if they want to bargain an item even lower and won't take a great offer, cool, I don't need to sell, but I don't have the time to waste to engage with them. Had something on Vide where I sold a 3K dress for 150 and she kept on sending messages if this is really my last word, mentioned when she needs it, finally bought it for 150 and then tried to return (I was a bit *****y and timed it so that it would arrive early, so the day she needs it is past the return time) and promptly she tried to claim she got it only on the 15th, however tracking showed that it arrived on the 12th and she signed for it, since I could show the evidence in tracking and with the screenshot, they denied her return request and warned her.