O2 Contract Deals If you are thinking of purchasing a mobile contract, you'd want to sign up for only the best, right? If your answer is yes, then you should sign up for an O2 contract phone. Why O2? Because O2 has over 40 million satisfied customers all over Europe and this is a company that you can truly rely on. Moreover, O2 contract deals are perfect for all kinds of budget. O2 contracts also come with the most amazing handsets from Nokia, Sony Ericsson, Samsung and LG