Also known as 'reverse billed' messages, premium rate text (SMS) messages come from four, five or six-digit numbers and are normally for subscription services such as games or weather updates.
SMS text messages of this kind can only be sent out if you sign up to the service.
There are several scenarios where you should check the small print before you sign up to a text service, so you know exactly what it will cost.
Unfortunately a lot of people subscribe to premium rate text (SMS) messages by mistake – for example, by failing to tick or untick a box on a website or replying to a message.
This means you should be even more careful when entering competitions or registering for a service.
Think of your phone like your credit card - if you give out your number, you could be charged.
Unless you're really confident you know how a website will use your number, don’t enter it online.
Something that claims you could 'win a new tablet or phone' may seem tempting but it may not be all it promises to be.
When you come across adverts claiming you can win prizes, make sure you read the small print before entering.
Some mobile apps including games can send text (SMS) messages from your phone to a premium rate number.
Before you click download make sure you check what the app really does.
Don’t download apps from non-trusted app stores and always check the list of ‘app permissions’ before you download.
Mobile marketing text messages often come from short numbers usually beginning with 5,6,7,or 8 – for example something like 7474.
Texting to these shorter mobile numbers - call mobile shortcodes - can cost more.
These numbers are often used to pay for new features in apps, to donate to charity, to enter competitions and to download games.
You may see these numbers in promotions asking you to text a certain word to a number or, you may receive promotional texts asking you to reply to them.
Be aware that if you do text these numbers, you may be charged a premium and you may also be signing up to unwanted text messages, premium or otherwise.