Yeah, I gotta say I would recommend the classes, especially as the Marie Mongan book is geared to an American audience so half the book might frustrate you, on its own. My classes were $350 but probably because we went to her house (less overheads compared to her classes in rooms closer to the city, and more convenient for us to go to her anyway), but I would have paid the $400, especially with hindsight. Yes, it was expensive, but I projected into the future of no HB and pictured myself wishing I had paid the money to have a better experience. It was really worth it to learn specific techniques to achieve the birth that I wanted. I might have been able to do it without the classes, but I didnt' want to leave it to chance.
But then again, being that I haven't NOT done the classes, I can only recommend one way with any authority!
Hey, good luck and have a great birth (cos it CAN be done )