I hope it is okay to ask this...

As I stated in my introduction, I am wanting to welcome a cavalier puppy to our family. I would love to adopt a puppy from a proper breeder.
If a puppy was sold with papers and registration, microchip, dewormed, vaccinations up-to-date, EU passport, and written guarantee, what would be the realistic cost of such a puppy?

I'm sorry if this might seem a bit odd of a question to ask. It's a bit hard to ask such a question as it involves putting a price on a living creation and I dislike that notion but at the same time, I think it is good to know what can be expected. (Kinda like when we had our small garden quoted for landscape work thinking it'd be 5000 but we were quoted 18 000) It's also hard because I am new in this country and know that things vary from country to country as well. I figure that perhaps the Netherlands would have a similar range as the UK? I have read that I can expect a puppy to cost between 500-800 and I am wondering if that is actually realistic or if that is too low. On the other hand, I wouldn't want to be overpaying either. I'm trying to have a basic idea of what cavaliers normally cost?