A month or so ago I posted a note complaining about how the Tome cost 375pp on one server and 6gp on another. At the time, based on suggestions from the people here, I sent a in-game bug report about the discrepancy.
I hope that what I'm about to say isn't old news.
Last night I was playing a monk on the server where the vendor was charging 375pp. I thought it might be time to check the price again and voila! The price was now 9pp. Totally reasonable and I bought the Tome!