Martin Lewis has urged everyone that owns a mobile phone to send two texts to cut their bill before prices rise in April.
Speaking on his ITV Martin Lewis Money Show Live on Tuesday night, the financial guru explained it is important to check how much it would cost you to leave your current contract.
To do this, text INFO to 85075 on your current phone.
You should then get a message back to see if you have any exit fees to pay if you leave your supplier.
Texting 85075 is free to do and gives you up to date information about your current contract.
The second message allows you to switch over your current number to another network if you do decide to swap over.
If you want to keep your number, text PAC to 65075 on your old phone, they will send you your PAC code and you use this with your new provider as a way to keep your old number.
Martin warned how phone bills are set rise by 14% this spring - meaning it is important to check if you can get a better deal elsewhere.
Martin said: "Last week I told you broadband and mobile bills are going up 14% in April for most of the big firms.
"What I want you to do first is I want you to check if you're out of contract. Over 9million of you are and are overpaying.
"What you need to do in most cases is text INFO to 85075 on your current phone. And that should tell you whether you have termination fees to leave your contract."
However, people who do have fees to pay may not be able to save the money right now, Martin said, so they will have to wait for a better opportunity to do so.
But he added: "If you're out of contract there are actually some of you - outrageously and this should not be allowed - who got a contract with a handset and once you paid the handset off, they keep the price at the same level so you're still paying the with-handset price even if you're no longer using it."
He added: "If you want to keep your number, text PAC to 65075 on your old phone, they will send you your PAC code and you use this with your new provider as a way to keep your old number.
"Of course you could use this as a way to haggle with your existing provider."
Seven ways to slash the price of your phone bill:
If you’re happy with your handset, you can save a fortune on your next bill by keeping it once your contract ends.
If you’re holding on to your smartphone, search for the cheapest SIM-only deals by using comparison sites such as MoneySavingExpert, Uswitch and Go Compare.
If you've found a deal you're happy with, you can keep your number instead of changing it by following Martin's advice above.
For users who are unhappy with their current phone, or would like a change, they could look at getting a cheaper refurbished phone from major seller such as eBay, Amazon, O2 Like New, Music Magpie or Mobiles.co.uk. It is important to always check reviews before buying though.
You could consider getting a bundle contract, as it may work out to be cheaper per month.
Once you’ve found the cheapest bundled or SIM-only tariff that suits you, look at signing up to quidco.com and topcashback.co.uk to see if the provider is offering a bonus.
It is important to check whether the provide you're looking at signing up with has roaming fees. For example, EE, Vodafone and Three all charge up to £2 a day. But providers like Asda Mobile, BT Mobile and O2 don’t currently charge extra.
