Adding yourself to your parents insurance.

So I passed my driving test today, thankfully! Now I just have to get insurance. So I was wondering how much extra my parent's will have to pay to put me as a second driver. I'll be driving my parent's car for good couple of months, until I get enough experience to get my own insurance, and car.

- How much does it cost to add someone as a second driver, in average? (Extra cost)
- A monthly quote would be nice! :)

Cheers!