It is not possible to pinpoint a certain mobile phone contract and say "this is the best of them all". The reason for this is because whether a particular contract is good or not depends almost entirely on what your personal needs and requirements are. But let us talk about some contracts which are generally favored by a lot of mobile phone users and so they can, in a way, be considered as one of the best.
Lifetime contracts: Lifetime contracts relieve you of the trouble of recharging your mobile phone every month to keep it active. You can recharge once and forget about it until your prepaid balance becomes zero. Then you can recharge some top ups, which are quite beneficial because you mostly get one hundred per cent talk time. However, some of these contracts, even if they call them 'lifetime' ones, are not literally so, because you have to recharge a certain amount every six months or so. However there are mobile phones which indeed offer free incoming calls for life and you must make sure you choose the correct ones.
Free SMS: Free short messaging service (SMS) is a great way to save. You pay a certain amount of money and you get a certain number of SMSs free over a period of say, seven days or 15 days or a month. These are especially beneficial for young and unemployed boys and girls using prepaid mobile phone connections. They can get their messages across to their friends while spending a meagre amount as compared to regular SMS costs. With hundreds of SMSs available for free, some people even do a kind of chat on the mobile phones via SMS.
Free calls between two mobiles: This kind of contract is exceptionally popular among couples. Both the guy and the girl use mobile connections of the same service provider and they can call each other for a certain period of time for free. Here, you need to pay a certain amount of money to your service provider and you get to call a particular number for free for a particular period of time. Some contracts even allow you to make long distance calls for free.
You can get into any of these three contracts and enjoy the benefits. But you must identify your requirements first. Without knowing what you want, you can never make the best use of mobile phone contracts.