The introduction of pay-as-you-go phones in the Nineties helped lots of people get their first mobile.

According to the latest statistics, 67 per cent of mobile customers still use pay-as-you-go phones.

Last year, the networks stopped subsidising them so they have become more expensive. Calls can also be more expensive and these tariffs are favoured by low and medium users.

It could be users would be better off choosing a pay monthly deal unless they are under 18, have a poor credit rating or do not intend to use the phone very much.

Pay monthly packages, used by 27 per cent of mobile users, enable the networks to recoup the costs of subsidised handsets and cheaper calls by getting you to commit to 12 months of line rental charges.

The majority of packages provide inclusive, or free, minutes but it is worth exploring the differences between tariffs on the same network.

The general rule is the more you pay monthly in line rent, the more inclusive calls and/or the lower the cost of calls beyond this allowance.

Call charges can vary between 5p a minute for offpeak calls to landlines to 50p a minute for peak-time calls to mobiles on other networks.

The other thing to consider is the cost of texting, which is the most popular service after making calls.

Voicemail is another standard feature but can be expensive, costing from 5p to 40p.

If you are planning to use the phone abroad, make sure you get a breakdown of your network's roaming charges to find out how much it will cost.

If you're really worried about controlling your costs, it might be worth getting your bills itemised.

This will highlight where most of the charges are coming from and help you decide if it is worth changing tariffs. A number of tariffs provide this service free but others will charge up to £3 a month.

Many tariffs offer "inclusive minutes" but it's worth checking what they include. Some only apply to same network calls, calls to landlines or calls made at certain times of day.

It is also worth establishing what a network means by peak and off-peak calls.