The second thing to consider is the general trend of the car insurance market to charge both young drivers and new drivers higher premiums due to the statistical fact that they are more likely to be involved in a serious accident, but also tend to make larger claims more frequently than most other groups of drivers.
If you have passed your test and become a new driver at the age of 17 there will be very few insurance providers willing to offer you temporary car insurance. There are slightly more who will offer temporary car insurance to drivers who are 18 but the majority have an age limit imposed of 21.
The best way to find a deal on temporary car insurance that is both affordable and suited to your needs is use the internet to look at all the many different companies out there in the market place. Price comparison sites are normally a good way to get car insurance quotes but may be of limited value when attempting to get such a niche car insurance policy.