In fantasy baseball auctions, value is like the '70s book (and movie) character Sybil, replete with multiple personalities.
There is the player's raw value, based on his statistics. There is the market value, which is how a majority of fantasy owners value the player. There is the intrinsic value the player has to your team. For example, if you already own a stolen base guy like Michael Bourn, fellow speedster Brett Gardner's raw value and market value do not change, but his intrinsic value to your team might (his value would go down). Finally, there is the bid value, which is the amount you decide upon after considering all the above permutations. In short, our job as fantasy owners is to pay as little as we can in terms of individual players' market value to assemble the roster with the most intrinsic value.