[syhprum (OP)]

Today I received a email from Amazon suggesting I purchase a device to reduce the power consumption of my cell phone charger.
I charge my cell phone once a week for six hours consuming .025 units of power at £0.1 per unit ie a weekly cost of £0025 or an annual cost of £0125.
The device costs approx. £10 and if the device reduced the power consumption to zero the cost of interest on the purchase price would be £0.5 per annum, I don't think I will be buying one .   

[Geezer]

Rats! I was planning on blaming our whopping electric bill on Mrs G's excessive cell phone use. Maybe it's something the dogs are up to that's causing it.

[CliffordK]

I wonder what the device is supposed to do.
Assuming you have the Cell on standby 24 hrs a day...  it isn't reducing the standby power consumption.
You still have to charge the battery.  You won't get around that.

Wallworts use a little bit of standby power, which you could decrease by unplugging them when not in use. 

Perhaps you should simply unplug your wallwort, or plug it into a switched power strip, and save the $20.

[SeanB]

Snake oil from Amazon? Cellphone chargers use so little power anyway that they are only noticeable in aggregate as a very small part of the overall supply load, down in the noise. A million chargers is a megawatt, but this must be compared to the total load being in the gigawatt range. On your household meter it probably is not enough power to overcome the friction in the meter movement, or less than the bit size in a smart meter.

[Nizzle]

... ie a weekly cost of £0025 or an annual cost of £0125...

Strange economy? Strange year I'd say, with only 5 weeks in it..