If Santa managed to squeeze a home PC down your chimney this Christmas, with one month's free trial of an Internet service provider (ISP) already loaded, you should have been able to start digesting Web pages before your turkey.

But as that month's free trial comes to an end, you'll soon have to decide whether to stick with your default ISP or choose from the handful of others out there. By sticking you get to keep the email address you may have already told your friends about, but by shopping around you might be able to reduce the cost of being online.

When shopping for Internet access, the first big questions are how to get online and from where. Chances are most new users will use modems and phone lines. While there are four ISPs offering local-call Internet rates to most or all of the population, there are also several which only offer this within smaller areas.

Using special numbers, Internet access calls to ISPs are charged at local telephone rates, except you get five minutes per unit rather than three during peak hours.

The larger ISPs for domestic users are Ireland On-Line (IOL), which is owned by An Post, Indigo and Tinet, which are owned by Telecom Eireann, and the new kid on the block, Esat Clear.

IOL is the biggest and oldest of these ISPs, claiming in excess of 40,000 customers. Its basic package for the home user costs £30.25 to set up, and £15.13 per month, or £151.25 per year.

For this, you get the usual Internet services (email account and access to the Web, news groups and chat groups), 5 megabytes of space for your own website, and an email address. For 97 per cent of the population, Internet-access calls to IOL are charged at local-call Internet rates.

The State's largest ISP also offers a family service. Costing £18.15 per month, or £181.50 per year, it offers an unlimited number of email addresses on the same account. This can allow different users to collect their mail separately, handy if you do not want to read 50 emails a day flying in from your children's favourite mailing lists.

Telecom Eireann's two ISPs, Indigo and Tinet, charge different rates.

Indigo, the older and cheaper of the two, charges £15 to set up a basic account, with a £121 annual fee. For this you get an email address, the usual Internet access, and 5 megabytes for your own website. Multi-user accounts cost another £121 per year.

Indigo has State-wide local-call numbers for sales and Internet access, while customer support is provided via a Dublin number.

For its part, Tinet charges £12.50 for a starter kit, but for those who already have Internet access, online registration is free. The first month is free, and thereafter it costs £14.52 per month, or £145.20 per year.

This gives customers three email addresses, 10 megabytes of personal Web space, and the usual Internet access. All calls from within the State are charged local-call Internet rates, while calls to customer support are charged at local rate too, a big advantage for non-Dublin based beginners.

Remember the cost of being online also includes the cost of the phone calls to the ISP. Hence there are demands for flat-rate calls to ISPs, which will suit the heavy users but will undoubtedly place an extra burden on the ISPs, who will require extra modems and phone lines.

Bucking the trend therefore, Esat Clear is not charging a monthly fee but an extra fee on top of the normal telephone charges for Internet access. It does have a £20 registration fee, but after this all calls to the ISP are charged at 3p per minute during peak hours, and 1.7p per minute off-peak.

Because its charges include telephony costs, it works out cheaper than other major ISPs for light Internet use.

For example, using the above figures, Esat Clear works out cheaper than the other national ISPs for up to 18 hours per month usage off peak, or 24 hours per month at peak rate. Thus it is targeting new users. Like Tinet, it offers users 10 megabytes of personal Web space.

However, if you know you are only going to be calling your ISP from one location, it might be worth checking out ISPs which only provide local-call dial up from your own area.

Dublin's Club Internet, for example, charges £99 per year, with no registration fee and unlimited Web space, while Connect Ireland charges £85 per year with no registration fee and offers 5 megabytes of Web space.

Further afield, in Westport for example, ANU offers two email addresses and 5 megabytes of Web space for customers in Mayo and north Galway for £165 per year, with a £15 set-up fee.

But ISPs do not just vary their prices; the quality of service varies too. Shopping around might also get you an ISP where the phones are less busy, or with faster links to the websites you visit, or with better technical support. Unfortunately, the nature of the Internet access business is that ISPs are constantly upgrading. The quality of service often gradually slips as new users register, until new equipment is installed or additional technical support staff are hired and "normal" service is resumed.

The quality of your local phone lines may also determine whether your 56 kilobits per second modem gets close to its potential. Internet newcomers who want to know how good an ISP's service will be are advised to either contact existing customers or take out a free trial.

But if cost is the only issue, then Esat Clear may offer the best bargains for light users, while Indigo or local ISPs may offer the cheapest bets if you prefer to pay monthly or annually. If you foresee lots of calls to customer support, then Tinet's local-rate numbers become attractive, while if your whole family wants separate email addresses then IOL may solve the arguments.

Eoin Licken is at elicken@irish-times.ie