There is something you can do to estimate a seller's reserve bid even if s/he won't tell you what it is. Go to the "Sellers" file off the main eBay Search menu and check out the seller's past track record. Very often you can see a relationship between the opening amount set and the hidden reserve bid. Other sellers have reserve bids that are many times higher than their opening amount, so that there's really no relationship between the two figures. Those sellers are easily spotted because they don't sell many of the items they put a reserve bid on.