Mark Bridge writes:

I like a challenge. I like learning. Ask me to do a spot of research and I’ll happily pore over books, trawl the internet and have lengthy conversations into the night.

So I was more than happy to help when Optomen Television, the company behind “Britain’s Secret Shoppers” on Channel 4, asked me for a few tips that would help viewers get a good deal on a mobile phone. And I didn’t need to lock myself in a reference library because I could delve into my personal experiences instead - from managing a mobile phone shop to writing ads on behalf of the UK’s biggest mobile network. This was going to be fun.

It was a surprisingly sunny afternoon towards the end of 2012 when I met the Optomen production team at Phone City Direct, the independent phone shop in East Finchley that was to serve as an attractive backdrop for our filming. Fuelled by coffee and some kind of festive muffin from the nearby Costa store, I was ready with a collection of handy money-saving tips that covered everything from roaming to recycling.

Three hours later and we’d recorded an assortment of those tips, although there wasn’t time to get every single one into the programme.

Fortunately, I’ve remembered them all. Here’s a summary of those tips for saving money if you’re looking for a new mobile phone or a new price plan. (Alternatively, if you work in the mobile industry, here’s a reminder of the things your customers are likely to be thinking about!)

Upgrades: if you’ve already got a mobile phone and want a new one, ask your mobile network if they can do a deal for you. If you don’t like the price, threaten to leave and see if the deal gets better. Talking to the ‘customer retention’ or ‘customer loyalty’ team may well get you a special offer that isn’t available to other customers.

See the bigger picture: do some basic maths before you buy. Multiply the monthly charge by the minimum term of your contract, then add the phone cost. Paying £99 for an iPhone and then £30/month for two years is cheaper than a free iPhone and £35/month.

Consider SIM-free: sometimes you can get a better total price by looking at a ‘SIM-only’ monthly deal (i.e. a deal that doesn’t include a mobile phone) and then buying the phone without a contract from somewhere else.

Check the calendar: if you bought your mobile phone and signed your contract at the same time, take action when the minimum contract term is over. It’s often worth moving to a ‘SIM-only’ tariff as soon as you can.

Sell your old phone: check all the major online mobile recyclers as soon as you’ve bought a new phone - and sell the old one quickly because prices drop fast.

Check the extra charges: make sure you know how much you’ll be paying for voicemail, picture messages and going over the limits on your tariff.

Compare: if you're not sure about usage when choosing a tariff, there are online comparison sites that let you enter details of your recent calls to work out exactly what kind of tariff you need. However, bear in mind that your usage may have been influenced by your last tariff. If you’ve been given 100 texts per month, you may have been texting a lot just because you could!

Don’t necessarily think big: look at some of the lesser-known network names for good deals, especially if you already have a phone. Mobile virtual network operators (MVNOs) have done deals with the big networks that let them create deals tailored to certain types of customers. For example, you may get cheaper international calls or a better allowance of mobile data.

Avoid prejudice: don’t assume that ‘pay as you go’ isn’t as good as a ‘pay monthly’ contract - but also don’t assume that a contract is better. In some cases ‘pay as you go’ deals are pretty complicated, making it difficult to compare them with other tariffs and also causing you to lose out if you make a mistake or don’t completely understand them.

If it's broken, fix it: don’t throw your phone away or drop it in the recycling bin if the screen’s damaged or the battery doesn’t charge. It’s sometimes worth paying for a repair even if you’re going to sell the phone afterwards. Just make sure you ask for a fixed price before the repairs start.

Think carefully about insurance: don’t ignore mobile phone insurance - but don't sign up for it without thinking. Home insurance may cover you and sometimes banks offer a package of benefits that include phone insurance. Remember you’re still committed to the remainder of your contract even if your phone is broken or stolen.

Use WiFi: if you have a smartphone you can connect to your home broadband and free services in coffee shops by using WiFi. It’ll save your mobile data allowance for when you really need it – and it’s probably faster for browsing and downloads, too. With the right app you can save even more money by making free phone calls over the internet.

Be careful abroad: charges are very different when you go abroad; something the mobile industry often calls ‘roaming’. To start with, you pay to receive calls – and that can make voicemail messages pretty expensive. Quite often it’s cheaper to buy a ‘pay as you go’ SIM card from a phone shop in the country you’re visiting. And if you’re in any doubt, just turn your phone off completely and leave it at home.

Commission: every time a mobile dealer sells a phone and a contract, they’re paid commission. As a result, they’re quite happy to spend some money in advance if it means they get the sale. Sometimes there may be ‘free’ gifts, sometimes there may be discounts. Just like any other offer, make sure the total package is good value for you. In most cases, you’ll find that independent dealers can be much more flexible about pricing than the big names on the high street.

Family discounts: you may be able to get a special deal for more than one mobile phone on the same contract. However, there are a few things to watch out for. Firstly, these might not be available from every phone shop on the high street. Secondly, putting all the phones on one contract means one person is responsible for the whole family’s bills. And finally, if you’re sharing an allowance of calls and text messages, it’s also possible for one person to use them all up. There can be big savings - but there can also be big problems.

Mark Bridge is the technology writer who was offering mobile phone advice in Britain’s Secret Shoppers on Channel 4 television this week. He’s also one of the presenters on The Fonecast.