But BT and Virgin have launched new apps that promises to slash holidaymakers' mobile costs abroad.
Let's take a look at these and other apps that can also be used to cut the cost of your calls home.
BT's new SmartTalk app works by linking the customer's smartphone to their BT home calling plan. Customers can then use the inclusive call allowance on their calling plan on their mobile wherever they are.
There's also the chance to save when calling outside of your inclusive minutes as BT's standard landline rates will then apply, instead of expensive mobile rates.
Another advantage to the app is that some BT calling plans include 0845 and 0870 numbers. So, using SmartTalk, you can call these numbers free from your mobile. And numbers that are free on BT landlines, such as 0800, can now be free when you call them from your mobile phone using SmartTalk.
The app, which is free from the App Store on iPhone or Google Play on Android, works best over wi-fi. In theory it works over any mobile data connection but you'd be at the mercy of data roaming charges if you used 3G.
Virgin Media SmartCall
Rival Virgin Media has designed a similar app to BT SmartTalk with a similar-sounding name: SmartCall.
It launched in November to "select customers" and is expected to be made available to all Virgin Media customers soon.
It will work in a virtually identical way to BT SmartTalk by allowing Virgin landline customers to use the unlimited calls from their home phone talk plan on their smartphone over a wi-fi connection.
If you're on a BlackBerry, you can save on overseas voice calls from your mobile with BlackBerry Messenger.
The latest version, BBM7, allows users to make free voice calls to other BlackBerry users over wi-fi.
BBM Voice allows users to either call a fellow BlackBerry owner directly or instantly switch from text to talk and back again. There's also a split-screen feature so that users can talk and text at the same time.
Skype became a major threat to the landline market a few years ago when it enabled users to make free calls over the internet for free.
Inevitably there are a number of Skype apps available for iPhone and Android which allow smartphone users to make Skype calls from wherever they are.
The apps are best used on wi-fi (if you use 3G you'll be charged for data roaming) and allow users to make video or voice calls over the internet for free if the other person has Skype too. If the person you're calling doesn't have Skype you can make cheaper international calls to landlines or mobiles using Skype Credit.
If you just want to send text messages rather than make voice calls, Whatsapp is a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS.
Already used by pretty much everyone under the age of 25, WhatsApp Messenger is available for iPhone, BlackBerry, Android, Windows Phone and Nokia. It allows users to send text messages over wi-fi rather than the mobile network. This means text messages won't come out of pay monthly customers' text allowance and PAYG customers won't be charged. Travellers can avoid charges for texting to and from abroad.
In addition to basic messaging WhatsApp users can also create groups, allowing you to send each other unlimited images, video and audio media messages.
All the above apps need a wi-fi connection to offer free or cheap calls. If you use the apps on 3G abroad you'll be charged for data roaming – and this can be expensive.
If you're travelling somewhere where you're unlikely to find wi-fi then a PAYG SIM could be the answer.
A local SIM card will offer much cheaper calling rates, both within the country you're in and to the UK, than using your normal tariff.
Bear in mind though that an international or local SIM will mean having a different mobile number while you're away and your phone will need to be unlocked for the SIM to work.
10 consumer rights you should know
How to make cheap mobile phone calls home from abroad
The law states that any goods you buy from a UK retailer should be of satisfactory quality, as described, fit for purpose and last a reasonable amount of time.
This applies even if you buy items in a sale or with a discount voucher. You may have to insist on these rights being respected, though.
Useful phrases to use when you want to show you mean business include, "according to the Sale of Goods Act 1979" and, if it's a service, "according to the Supply of Goods and Services Act 1982".
Some shops will allow you to exchange goods without a receipt, but they can refuse to should they wish.
If the goods are faulty, however, another proof of purchase such as a bank statement should work just as well.
If you attempt to return goods within four weeks of the purchase, your chances of getting a full refund are much higher as you can argue that you have not "accepted" them.
After this point, you can only really expect an exchange, repair or part-refund.
The updated Consumer Credit Act states that card companies are jointly and severally liable for credit card purchases of between £100 and £60,260 (whether or not you paid just a deposit or the whole amount on your card).
Anyone spending between these amounts on their credit card is therefore protected if the retailer or service provider goes bust, their online shopping never arrives or the items in question are faulty or not as described.
Start by writing to the agency asking it to either remove or change the entry that you think is wrong. It will investigate the matter and find out whether you have been the victim of ID theft or a bank's mistake.
Within 28 days from receipt of your letter the agency should tell you how the bank has responded. If the bank agrees to change the entry, they will authorise the agency to update their records. They should also send updates to any other credit reference agencies they use.
You can also contact your lender directly to query a mistake. If the lender agrees to the discrepancy, ask them to confirm this in writing on their letterhead and send a copy to the agency, asking them to update your file.
The FOS settles disputes between financial companies such as banks and consumers.
If a financial organisation rejects a complaint you make about its services, you can therefore escalate that complaint to the FOS - as long as you have given the company in question at least eight weeks to respond.
The FOS will then investigate the case, and could force the company to offer you compensation should it see fit.
Bailiffs are allowed to take some of your belongings to sell on to cover certain debts, including unpaid Council Tax and parking fines.
They can, for example, take so-called luxury items such as TVs or games consoles. However, they cannot take essentials such as fridges or clothes.
What's more, they can only generally enter your home to take your stuff if you leave a door or window open or invite them in.
You are therefore within your rights to refuse them access and to ask for related documents such as proof of their identity. If they try to force their way in, you can also call the police to stop them.
Private sector debt collectors do not have the same powers as bailiffs, whatever they tell you.
They cannot, for example, enter your home and take your possessions in lieu of payment.
In fact, they can only write, phone, or visit your home to talk to you about paying back the debt. As with bailiffs, you can also call the police if you feel physically threatened.
Thanks to the Distance Selling Regulations, you actually have more rights buying online or by phone than on the High Street.
You can, for example, send most goods back within a week, for a full refund (including outward delivery costs), even if there's no fault.
You will usually need to pay for the return delivery, though. The seller must then refund you within 30 days.
We enter into contracts all the time, whether it be to join a gym, switch energy supplier or take out a loan.
In most cases, once you've signed a contract, you are legally bound by it. In some situations, however, you have the right to cancel it within a certain timeframe.
Credit agreements, for example, can be cancelled within 14 days. And online retailers must tell you about your cancellation rights for any contract made up to stand up legally.