Brace yourself. With just 56 shopping days to Christmas, rivals in the mobile phone market are squaring up for all-out war.

The deals are already flowing thick and fast. Free TVs and accessories, reduced connection fees, extra call times for no extra charge. It is enough to make the first-time buyer's head spin. And it is set to get worse, or should that read better?

Esat Digifone is preparing to introduce its own pay-as-you-go mobile phone in direct response to the success last year of Eircell's Ready to Go. In the seven weeks before last Christmas, the product managed to attract 10,000 new mobile users a week to Eircell, the equivalent of Digifone's monthly customer growth rate.

The competition this year is being fuelled by more aggressive marketing from retailers, a number of whom have since been acquired by the two mobile phone operators eager to achieve a stronger presence in the high street.

At first glance, it all spells good news for the consumer who can pick up advanced mobile phone models for a fraction of the cost a couple of years ago. However, a policy of "buyer beware" should accompany anyone finding themselves dazzled by all the offers.

In a number of cases, hidden costs are involved as consumers may be asked to hand over a deposit or commit themselves to a yearly contract. In others, consumers may buy a phone only to find it remains owned by the mobile operator until a nine- or 12-month billing account period is cleared.

Take Eircell's Square Deal and Chatterbox offers, for instance. Today you could buy an Ericsson GA628, worth £215, including a connection to the 087 network, worth £42.35, for just £29 at any Eircell dealer. Moreover, if you connect to Eirtime 50 or 100 your inclusive Eirtime minutes will be doubled free of charge for the first three and two months respectively.

In return, however, Eircell expects loyalty. The offer is only open to first-time connectors who pay by direct debit and agree to stay connected for at least one year.

As a result, if you connect to Eirtime 50 and make 100 minutes of calls each month, half at peak time and half at off-peak, you will be charged only £72.60 in total for the first three months. But after that your monthly bill will jump by 56 per cent, resulting in an end of year total cost of £412.89.

Of course, you are under no obligation to continue making calls at the same rate but the operators are banking on you doing so, if not increasing your mobile use.

While switching to a cheaper Eirtime option is allowed, disconnecting before the end of the year is not. Any first-time connector who does not have a land-line with Telecom Eireann is asked to provide a deposit of at least £50, which goes towards paying the first rental bills.

"A lot of customers get the wrong impression about all these deals," says Mr Daniel Devignat, assistant manager at the Carphone Warehouse on Grafton Street in Dublin. "They just see the basic price of £69 or £99 and are lulled into a false sense of security. They think that's all they have to pay."

He says buyers should particularly be aware of the need for insurance at £3 a month. "Some people lose their phones and walk back in looking for another one at £99 only to be told they still owe money on the one they lost."

Without insurance, consumers must re-buy their original phone at its standard retail price - as much as £300 in case of some basic models - or else clear their annual account without a phone.

Less rigid conditions apply for first-time connectors to Esat Digifone who can pay by a number of means, although direct debiting is strongly recommended.

No written contract is agreed but, as with Eircell, buyers must give 30 days notice before disconnecting and Digifone may ask for the phone to be returned if it has only been connected for a short period of time.

Because Digifone has less protection from disloyal customers, it operates a points scale for all first-time connectors based on such factors as their credit rating and whether they pay by direct debit. Customers who do not obtain enough points may have to make a prepayment of as much as £250 before they receive their phone.

However, Ms Sarah Dempsey, press officer with Digifone, said "we don't so much go after people who don't use the phones as try to encourage customer loyalty as much as possible".

She added the company is expecting most of its sales this Christmas to come from its new Digipack choice range, introduced last week, especially the Digipack panache. The £69 offer includes a Nokia 5110 handset, a connection to the 086 network and one month DigiFlex line rental which, valued at £24.20, includes £9.08 of free calls.

"Christmas is the best period for certain brackets of the market," said Ms Dempsey. "While we'd have a steady flow of new business users all year round, new personal users, such as wives, students or parents, increase rapidly around this time."

However, the main battleground this Christmas between the two operators may prove to be the pay-as-you-go market, depending on whether Digifone launches its long-awaited pre-paid service.

"We are looking at such a product and we know the market wants it but we don't want to produce something that will result in a backlash like the Ready to Go unit," said Ms Dempsey.

The launch of Eircell's pay-as-you-go product last year was marred by a system failure on Christmas Day and St Stephen's Day when more than 25,000 new users simultaneously logged onto the network. But since then Ready to Go has continued to grow in popularity with more than 200,000 users at present, almost half of Eircell's total customer base.

The main advantage of Ready to Go is convenience. No connection or rental fees are involved. Instead, credit is obtained by purchasing £20 call cards. Once activated, each card is valid for only 60 days, which means consumers must spend a minimum of £120 if they want their phone to run all year round.

Unused Ready to Go phones can be reactivated with an SIM pack for £49, which includes £30 of call credit.

However, flexibility comes with a cost and, at 80p a minute per call at peak time, Ready to Go is the most expensive Eircell product to use.

It is possible to switch to a cheaper call package but only by committing to a yearly contract, as with Eircell's other offers. Switching phones, however, is not possible without incurring a sizeable charge.

When shopping for mobiles this Christmas, consumers should also be aware that the advice given by dealers is not necessarily impartial.

In recent months, Eircell has acquired one major retail chain, Lets Talk Phones, and is finalising a deal with Person to Person (P2P), while Esat Digifone has purchased a controlling interest in Cellular World. Digifone has also withdrawn its dealership from Lets Talk Phones amid claims that the retail company was directing customers away from Digifone to Eircell.

The move into retailing makes sense for mobile operators as it saves them paying dealers large "bounties" to attract customers to their network. It is debatable, however, whether the trend is of benefit to the consumer. Similar moves in Britain were resisted by the British competition authority, concerned about possible price fixing.

However, if the last few weeks are anything to go by, there is no fear of prices here climbing. The reverse seems more likely as both Eircell and Digifone vie for market position ahead of the start of the third mobile phone operator, Meteor, early next year.