Device A connects to the internet via a 3G (UMTS) cellular network. So does Device B. Same carrier, same cellular network, same UMTS technology used to transmit & receive data.
For Device A, a $30/month plan includes 2000MB of data.
For Device B, a $30/month plan includes 500MB.
For Device A, when you exceed your quota, you pay $0.06 per MB for excess usage.
For Device B, when you exceed your quota, you pay $3.00 per MB for excess usage.
Same network, same data, from the same websites. But Device B pays 50 times more per MB for excess usage.
Device A is a 3G wireless internet modem you plug into a USB port on your PC or laptop.
Device B is a phone - which is why I'm not objecting too much to the different included data, because that $30/month also includes a fair amount of voice calls.
However, if you consider voice calls to be yet another form of data, it gets much, much worse.
GMS voice calls use about 30kbps worth of bandwidth for a digital voice signal. That's 1800 kilobits per minute, or 225 kB per minute. 0.225 MB per minute. At the $0.06/MB rate, that's 1.35c/minute. At the $3.00/MB rate, that's a princely 67.5c/minute. The actual call rates on the plan for Device B are 80c/minute.
If we priced voice & other internet data at the excess usage rate of Device A's plan, it would cost Device B $5.23 for the included voice data, and $30.00 for the included internet data.
Not too bad, $35.23 of value for $30!
But it would cost $120 for the data included in Device A's plan, which suggests the *real* cost of data is something less than the $0.015/MB that the included data for Device A is charged at.
That would price Device B's plan at something more like $8.81 for the included data.
However, I can live with paying a bit more for the GSM voice data, if it's given priority transmission to ensure good audio (having bits of lag here & there is bad for voice call quality). So I can live with paying $30/month for something that costs the carrier less than $9.
The worst bit, though? If you actually used a combined total of 2000MB of data on the phone, you'd pay a minimum of $4,500.00 in excess usage fees.
If both devices use 3000MB, Device A gets charged $90.
Device B gets charged $7,530.00.
For the same data. On the same network.
How is that even legal???