I think it was a million in the show but at that time Tywin was at his peak power and had access to uudouls of gold so I think a lesser price would be more realistic
the million price tag was something that was off handedly said as a story plot point for describing how much certain people want those swords and how unwilling those that have them are to letting go of them
instead of making the savages united and gathering 2000 men armies because the mc needs a challenge push the story a little some pov 's how the island changed ........
for a mountain that castle is very good, but without it it is sorely lacking.
winterfel for all that it is called actually sucks defencively speaking. a good castle is build in a star not round