Can I buy a single policy if I am a dependent on someone else's student visa?

If you have separate student visas, then you can purchase 2 single policies. However, if one of you is dependent on the other's student visa, it would be best to purchase a couple's policy. 

The couple policy tends to be a lot more expensive than purchasing 2 single policies. Insurers have told us that the reason for this is that they typically have a lot of claims from couples when they come to Australia to study and become pregnant. The insurers, therefore, increase the premiums for couples and families policies to take this risk into account.