That will depend upon just what you want it for.
If you drive a cheap car, that has just about got through its MOT test and will not cost you a lot to replace, then you may just want to just get your car street-legal. Once upon a time a third-party policy would have been enough. If you had an accident which was your fault the insurer should pay for any damage or injury you caused to other people, and you'd either fix your your own car yourself, or scrap it and if someone stole it you'd just shrug your shoulders and buy another one. The problem is that third party insurance now is often even more expensive than comprehensive cover! Take a look at our article here. Looking for the most economic comprehensive policy? Be careful. That really low price might turn out to be the most expensive in the end, after you've paid for excessive penalties, charges and extras. See our article on cheap car insurance tricks that some insurers pull. And don't bother complaining to the ombudsman, they are all listed in the terms and conditions. You DO read them before you buy insurance, don't you?
Despite all this there ARE bargains out there. You just have to look around and compare benefits as well as costs - make sure that you know what you are buying and which extras, if any, you will be hit with before committing yourself. Every insurer has to make all the information available in an easy to find, and read, format so please, please do so and then you won't suffer from any unexpected extra expenses.