Earlier this year I received various cost estimates from private hospitals for my knee replacement in writing. They followed up by phone and email asking for a confirmation. I honestly do not know if that was legally required though. However, as all of them were very expensive, I went to a public hospital and got a verbal range-indication of the cost (half of the cost in a private hospital). I accepted verbally, nothing in writing. after surgery they presented an invoice lower than their cost-indication.
I was lucky, I had the time to explore various alternatives, no urgency.