“For example, if you want to go from Hakata to Kumamoto by Shinkansen you’d normally have to pay 4,610 yen (39 US samoleans), but with a “gachi” ticket any bohemian, beatnik, or hippy can ride for only 2,570 yen (22 US clams). That’s a 40% discount, daddy-o!”

I assume most readers will be interested in the prospect of cheaper travel. On the other hand, some Japanese-language students out there might be more interested in mastering the usage of “gachi” in modern Japanese. In that case, see

http://zokugo-dict.com/06ka/gachi.htm

http://en.rocketnews24.com/2015/01/11/aw-snap-yo-jr-kyushus-really-cheap-gachi-ticket-is-in-the-hizzouse/