I'll be honest, I don't understand "or best offer". With the limited exception of time focussed purchases (people who need the item then or not at all) I can't understand what it adds to a minimum reserve price, which then gives you the opportunity to receive more if someone bids higher. People aren't shy at offering you less than your buy it now, anyhow. Maybe it's just me.
I set the item at what I think is a fair price and if someone wants to make me an offer, I don't mind a bit of haggling, as long as they don't take the piss.
Coming in with a very low starting offer is just irritating. I declined the £20 and £25 offers, but I had another offer of £30 and made a counter offer of £33 which was accepted. I'm happy with that.
I also sold another item yesterday at the listed price (£20), though I probably would have accepted an offer of £15.
I've got another item to sell that I will probably put on as an auction (with a reserve) as it's something that seems to be quite popular on ebay and usually fetches good prices.
It's all a game, really. And just a way of raising a bit of cash for
my old tat desirable, high-quality items.