Kugayama
Moderator
@yuki.n According to this page, the average monthly salary for ages 20-29 (what I assume to be Kalafina's main audience) is 2874120.63円 ($28268, €25144,99). Basically, one music box takes up around 1.5% of their monthly income, if I calculated correctly.
Big thanks to Google money converter
Hopefully that's not too much info
3761000 yen per annum for 20-29 year olds (strictly speaking one should use the term "salary" for monthly, and say "annual income" for yearly);
so: 313417 yen per month
which is about USD$3080 per month or EUR2740 per month.
19000 yen is over 5 percent of an average 20-29 year old Japanese person's monthly income, or in other terms about double the cost of a premium concert ticket or double the cost of a blu-ray of a live concert.
At Animelo Summer Live 2016, a towel, multi-coloured light stick and concert book came to close to 10000 yen, so 19000 yen is pushing to the premium level of souvenirs.