An out of pocket cost is the difference between the amount a doctor charges for a medical service and what Medicare and any private health insurer pays. Out of pocket costs are also called gap or patient payments.
The expiry date of your current OSHC policy is printed on the front of your OSHC card. It is a condition of your student visa that you maintain your cover for the duration of your visa. Make sure that you are aware of your expiry date and renew your cover before it expires.