I was intending to buy an item which had a "Buy it Now" price of £275 but also allowed for the use of "Best Offer".
I offered £250, £260 and £270, each time the offer being auto rejected.
Having no more offer chances available, I sent a message to the seller to find out the point at which a "Best Offer" would be accepted and he told me... £274.99"
As I said - what's the point?