People looking to cash-in their old mobile phones as they upgrade to the iPhone 6, iPhone 6 Plus or any other device could find themselves up to £79 out of pocket if they don't compare prices, has found.

As the latest iPhones hit the shops (see the Apple launches iPhone 6 and iPhone 6 Plus MSE News story), sellers are expected to flood online mobile buy-back websites to offload their phone for cash.

But we're warning people not to be hasty when it comes to flogging their old handset to help fund their upgrade. People selling the iPhone 5 have the most to lose – up to £79 – if they don't do an online price comparison before sending off their handset.

People can often get more by selling through an online auction site but those tempted to trade-in at a store will often get a poorer deal, so always compare prices before you commit. .

Here's how much we found you'd get for the top ten most searched for phones on our website:

Highest and lowest prices for the top 10 most searched for phones

Rank (i) Handset Lowest Highest price Price difference
1 Apple iPhone 5 16G £135 £214 £79
2 Apple iPhone 4S 16GB £90 £122 £32
3 Apple iPhone 5S 16GB £216 £272 £56
4 Apple iPhone 4 16GB £60 £103 £43
5 Samsung Galaxy S3 £61 £98 £37
6 Samsung Galaxy S4 Mini £80 £91 £11
7 Samsung Galaxy S4 £140 £171 £31
8 Blackberry Curve 8520 £3 £25 £22
9 Blackberry Bold Touch 9900 £25 £54 £29
10 HTC Desire £2 £47 £45
Prices compared on Mobile Valuer, assumes mint condition, correct at 19 September 2014. (i)The phones are ranked by search popularity on Mobile Valuer.

'An old phone can be a cash cow'

Guy Anker, managing editor at says: "The first message for anyone upgrading or simply with an old phone sitting in their drawer is not to let it gather dust, as it can be a cash-cow.

"But don't get seduced by the glitzy TV ads, as a quick search online before getting their new handset can mean they get much more than plumping for the first mobile recycling site they see. Our research this week found the difference between the best and worst payer was £79."

How to use reselling websites

There are a few rules to follow when using mobile phone resellers, which are:

  • The better your phone's condition, the more you'll get. 'Working' phones should generally switch on, have the original battery, and only have mild cosmetic damage. If your handset's not working, you can still flog it but it'll be for less. Most sites have an option for this.

  • Ensure there are no Pin or security locks, wipe personal data and restore factory settings.

  • After inspection, if it's not up to scratch the company may offer less. Don't be afraid to ask for the handset back.

  • If you send your phone off and the company goes bust or something goes wrong before you get the cash, you've little protection.

See our mobile selling guide for more tips on how to earn £150 for unused handsets.

How to make even more money

Selling your old mobile, tablet or camera online through a reselling site is quick and easy but the best way to get max your cash is to sell via an online auction site, such as eBay, although this is a longer process.

For more information on how to do this, see our eBay selling guide.