"If you are in Australia, double check, because the rules differ in the different states/territories."

It is complicated here.

While it is legal to own an e-cigarette device the TGA (similar to the FDA) has ruled that it is not legal to buy nicotine-containing products for them without a prescription. This is under review and I suspect that it will change.

There are many shops (on-line and physical) where you can buy nicotine-containing products for e-cigarette devices - I don't know if they enforce the "prescription-only" rule.