Get the lowest accepted price for eBay "Best Offer" items.
You may be aware that if you submit an offer that is declinded 3 times on a "Best Offer" or "Buy it now or Best Offer" item, then you are blocked from making further offers.
A lot of sellers auto-decline if an offer is not above a certain amount.
However, if these are power sellers, they often sell the same item multiple times, over a period of a few weeks, to sell the bulk stock that they may have.
This allows you to search for the item that you want, then tick the "Completed listings" box on the left. If it is a Power Seller, it's likely that you will find the same item that you are wanting to buy.
From here, you can then view the bid/offer history, and see what the lowest accepted price is likely to be.
This is very handy, as you can't see the bid/offer history on current "Best Offer" or "Buy it now - or Best Offer" items, obviously so that everyone doesn't just offer the lowest that's been accepted on the current item.
Hope this helps someone.
(It's just saved me a few quid)