Benefits of being rich.
A £150 round trip ticket in 1957 is the equivalent of £4,600 today, and in an era when average wages were around £400 per year [0].
Taking months off to bum around the hippy trail in the 1960s spending almost half of the average person's salary would have put you in the upper middle class to say the least. Alternatively, imagine spending £15,000 on a multi-month trip in 2026 like going to Antarctica, ascending an ultra, participating in the Dakar Rally, or racing the Iditarod.
Plenty of Brits in the era (especially the lower middle class and upwardly mobile) would have decided to spend that money on a ticket to move to Australia, Canada, New Zealand, or America instead.
An incredible return on investment. I bet many ended up with higher wages, better health, better housing etc (though I think about 1/4 ended up returning, at a large expense)
From there you can easily extrapolate how much it deviated from contemporary wages (roughly 30,000 Austrian schillings a year for a Viennese industrial laborer with a union contract in 1964).
A lot of people who think they are from middle class backgrounds are actually in the upper cream of society but never realize it.
Here's economic data for wages and household income in Austria back in 1965 [0] (page 2 and 11).
[0] - https://www.oecd.org/content/dam/oecd/en/publications/report...
I'm curious about the passengers on the bus and doubt everyone went the full distance on it.