I read it. I don't remember paying that much for it, but it was a number of years ago, so I suppose it is possible.
I found it useful with a couple of additional tips (about how you can set your employer up to see you are no longer necessary, train your replacement and amicably take a severance package), but ultimately although I've changed jobs 3 times since then I was never able to apply it. While I am a huge Financial Samurai fan, there wasn't anything earth shattering.
If I was not just taking another job but actually retiring, then this book is worth the buy. So for your FIRE folks - this is a great way to get a last little cushiony send-off!