I think the fact that nobody has announced a cheap low-end Blu-Ray player yet means diddly-squat, considering there are what, 3 units officially announced so far?
As for the PS3, realize that a large part of the price of these things is the processing power needed to decompress the movies in realtime - HD-DVD players, for example, are basically full computers running on Intel CPU's and running Linux. But PS3 will already have an uber-powerful CPU inside, one that has already been proven to be great for media (showing like a dozen Mpeg 4 movies at once), so that price will be built into the system. So for PS3, you can't just take the price of a Blu-Ray player and add it to the console price. Really, the only extra would be the extra it costs to manufacture the Blu-Ray drive with its blue laser instead of a DVD drive, which I can't see costing much at all to manufacture. That doesn't answer how it will be seen by competitors, but remember the PS2 did the exact same thing with DVD players - when it launched in Japan, the PS2 was cheaper than stand-alone DVD players.