One day car insurance is not just easy to buy it is actually easier to set up a 24 hour policy than it is to get a conventional annual one. This is because the application form has been greatly simplified, with far fewer questions for you to answer. The intention is to make it as quick and easy to buy as possible, because a very high proportion of the policies that are sold are bought by people who need to get cover at short notice and who are just as likely to be using a smart phone or tablet device rather than a computer to fill in the application form, and they simply do not want, nor do they have the time, to wade through reams of questions about everything from their marital status to their mother's maiden name!
Costed on a day-to-day basis 24 hours of cover is more expensive than it would be for 24 hours of a yearly policy but it is not designed for long term use, rather for those odd occasions when you need cover for a short period of time on a vehicle that you do not usually drive, or for when you may need to lend your own car to someone else temporarily. Compared to the potential costs of being prosecuted for driving without insurance or allowing a vehicle of your own to be used by an uninsured driver the price of a single day policy could seem insignificant indeed.
There is no guarantee that you would qualify for cover of course; for instance most insurers would expect you to be at least 18 with a full licence you had held for a minimum of 6 months or even a year, and each one has a rigid list of makes and models which can be accepted but most applications are successful and getting a quote should take you no more than a minute so it's worth a try, isn't it.
Allow one minute or so for a quote, two or three more minutes for the formalities then you could have a policy in place almost immediately once you have accepted a quote or you could book it to start at some other time in the near future if you wished to do so.