I've experienced this first hand as well. When Raja was a puppy he had lots of health problems and we made a few visits to the emergency vet hospital. They wouldn't even call the doctor out into the waiting room until we paid $200 deposit! (I was shaking, crying, completely a mess just waiting for a doctor to come out and tend to my boy!)
Thank goodness for Raja's dad and his credit card

which really took a beating in those months. Back then I think insurance would have been worth it but we had no idea what was in store for us concerning his health.
You would think people in this profession would care enough to start treatment immediately but even the doctor at this hospital was extremely rude & inconsiderate. She told us we bought a sick dog and we needed to go return it for a refund b/c it was too expensive in the 1st place - as I'm in tears and trusting HER to save his life, all she can talk about is a price tag?!