Yeah Sangaria is the budget brand in Japan.. When you see a 100 yen drink machine in Tokyo, it's usually Sangaria (or worse!)
The best melon/squash cider I've had was brewed right there with hotspring water in Arima (near Kobe, IIRC)
As for the flavour, if you've smelled those "squash" air fresheners, it's the same flavour. Obviously not as sickly sweet of course.