Is life insurance necessary to have?

Last week I was really struggling to find myself some good deals for life insurance. The whole thing was so confusing, as I am really bad in understanding of the terms. Couple of my friends explained the things to me and I kind of understood the terms better. Then I started searching for good deals on life insurance and filled in couple of forms over the weekend. I checked moneysupermarket and the cheapest I could get was £6.17but this morning someone from onlyinsurance called me and gave me a quote £5.90 a month.
I thought they offered me a good deal and said yes to them to go ahead with my life insurance. Do you think that they really gave me a good deal? their website is

http://www.onlyinsurance.com/Life-Insurance/

I appreciate if you could tell me about your thoughts and whether I made the right choice. When I was checking their website I understood they are not only doing life insurance but all other type of insurance too. Has any body heard about them? the website I was checking is http://www.onlyinsurance.com/Life-Insurance/ I also appreciate if you could suggest me any other websites which you think I can get good deals as I am also looking for a cheap car insurance.