with the 50 billion yen mentioned again I converted it into euro.
I arbitrarily chose June 15th 2006 yen, since that's my guess as to when Usogui is taking place due to that being the first year it started serializing, converted that to June 15th 2006 euro, and then converted 2006 euros into Jan 15th 2025 Euros.
That 50 billion yen would be 519,538,801.44 Euros in todays money, so that's half a billion that 50 billion yen is actually a substantial amount.