I'm young, healthy, etc too and I've been in an ambulance three times and attended an ambulance station one more time for treatment. Most of those happened while I was a teenager (head injury that required stitching, broken and dislocated fingers, serious abdominal pain, sun stroke), so not just something that applies to adults. All were acute and couldn't have been predicted. My DD has once required the ambulance when she got a bad cut to the head as a six week old which was bleeding heavily.
One time when the ambulance was called for me, I wasn't in a state to object. For that trip I received the bill (which I then passed on to my PHI, I was too out of it to give it to them at the time), it was about $400 from memory, and that was for 15 mins drive with no medical procedures at all. Literally being wheeled on and off the trolley and driven to the closest hospital. Another time after a car accident I refused ambulance attendance and got a friend to take me to the hospital to get checked (I had concussion). Really, i would have been far better off not freaking out about the ambulance cost because I had forgotten to renew my subscription and getting medical attention much more quickly. I had rolled the car down an embankment and didn't even realise I was that banged up until well afterwards.

