The cheapest mobile tariffs ever!

Tesco has launched one of the cheapest mobile tariffs available. But how does it size up to other super-cheap deals?

We've come a long way since the launch of the mobile phone. With five main networks now to choose from, and even supermarkets getting in on the act,  networks are fighting hard for a slice of the communications pie.

This means prices are falling, which is is good news - though the trade-off means you'll probably need to sign a longer contract. Eighteen-month contracts are now the norm, and 24 month contracts are slowly becoming more popular. So if you're not careful, you could end up tying yourself into a deal which quickly becomes uncompetitive.

One way around this is to take out a SIM-only tariff. Designed for people more interested in value than owning a flashy mobile phone, these pay-monthly plans only require a 30 day commitment, meaning you could get a great deal without being tied in to a contract.

You don't have to give up your number, either - you can easily port it over by obtaining a Porting Authorisation Code (PAC) from your existing provider.

How competitive are SIM-only tarifffs?

Very competitive indeed. Several providers have just launched SIM-only tariffs costing £10 or less per month.

Here's what's on offer at the moment:

In an exciting move this week, Tesco announced it was also joining the £10 club, launching its self-professed 'credit crunch buster of a tariff'.

Tesco's deal is similar to T-Mobile's Flext offering, where instead of being given a set number of minutes, your £10 payment is converted into £40 worth of 'credit'.

This credit can then be used for any combination of minutes and texts you like, as well as picture messages and web browsing.

In this way, you could get up to 400 minutes, 800 texts, 160 picture messages or 10Mb of mobile surfing - all for a £10 top up.

Personally, I think this is a great flexible plan. After all, you'll probably never use the exact same number of minutes and texts each month, so it's good to have the freedom to mix and match.

However, the cheaper rates only apply to five of your 'favourite numbers', which you nominate by calling customer services. These can be any fixed line or UK mobile numbers, and you are free to change them once every 30 days.

Depending on whether you nominate numbers or not, you could use your credit to get 200 minutes and 400 texts to your favourite numbers, or 100 minutes and 200 texts to non-favourites. So as you can see, the secret to making the most of this deal is to nominate those five most treasured friends and family members.

Simplicity

Nominating the favourite people in your life can become a bit of a popularity contest, and if it's all to much to bear, I think O2 comes second for overall value. With 150 minutes and 300 texts included, the O2 Online Simplicity 10 plan proves good value, and doesn't require any extra action to benefit.

One other feature exclusive to O2 pay monthly and Simplicity plans is texts sent from abroad are included in your price plan. One roaming text or media message is the equivalent of four messages sent in the UK - a handy feature for those who want to keep in touch while abroad, without being hit by some of the inflated charges.

If you have a lot of friends on the 3 network, you may also want to consider its SIM-Only, where you get an extra 300 3-to-3 minutes on top of the 100 minutes/texts allowance - a handsome boost to its value tariff.

The perks of pay monthly - for less

If getting a new handset is important to you, then a new plan from Virgin may be worth considering.

At £8.50 per month, it's the cheapest monthly plan available, and unlike the deals listed above, includes a free phone (not the snazziest models admittedly, but still enough to boost your street cred).

The downside of getting a new handset is you'll have to compromise on minutes. You'll only get 100 minutes and 100 texts, and have to commit to an 18 month contract. Still, for £8.50 a month, if your phone is on its last legs and you don't want to fork out for another handset, it is a good option.

If you prefer not to be tied in, Virgin's Liberty SIM gives you 200 minutes and 200 texts for £10 a month - with no tie-ins.

For low users, Asda mobile provides the cheapest plan for pay as you go users, with flat rate calls costing 8p per minute, and texts at 4p per message.

Unlike SIM-only, instead of commiting to a monthly payment, you only top up when you need to, providing a lot more value for those who only use their phones for emergencies. You can read more about pay as you go deals here.

So, that's a round-up of the cheapest tariffs available. Obviously these plans won't suit everyone, but if you are a relatively low-user and want more from your mobile, these great deals will let you talk more, for just a fraction of the price.

More: Seven clever ways to save cash | Slash your mobile bill in one easy step