The relaxation is just the first part. The second part is completely golf focused: balance and timing, course management, self management, target focus, and others. The visualization is from my experience playing NCAA Division I college golf. Like all golfers who have played a long time and at a high level I've read a lot of books, talked with a lot of people and tried a lot of different things. These are the things I found to be most helpful and are consistently utilized by the top level players.
As for the price, it's less than a large bucket of balls ($8) or a Subway Turkey, Bacon, Avacado sandwich ($9). With the currency conversion it's even cheaper in the UK at £3.99. Can you get a good bangers and mash for £3.99?