是当场就要交的。If you don't have money at hand, you can defer the payment.
Certainly you need to talk to the cashier for the payment options. Sometimes
they send you a bill later on if the amount is not determined on the spot.
That's why so many Chinese parents want to send their kids to medical school.
It's true the medical expense is quite high in US. Good health saves you
lots of money. :)
