@Ansu don't sweat the small stuff. If you hang-up yourself on this you won't be able to enjoy this and many other (isekai) series. Consistency isn't the forte here.
@Ansu The 100 million gold from chapter 5 is a terrible mistranslation. To be honest, the raws I can see don't even mention Kanaan's price so I have no idea where that number came from or how the TL got that. From reading the WN raws though, her price is 500,000 gold. So the math checks out that 10 million is 20 times 500k