During my stint in IIM-Ahmedabad, I'm a Uninor prepaid subscriber. The general plan tariff has SMS @25paise. A new SMS pack was offered for a month as follows:-
"Make the first 2 SMS's @ 50paise, next 100SMS/day free"
Apparently, it seems a great deal-pay just Rs 16 get 3,000 SMS's free. However, the first 2 SMS's would have cost Rs 0.5(.25*2) but now they cost Rs 1(.5*2). Thats a difference of Rs .5.day for 31 days approx Rs 16.
So, ethical marketing principles would have charged Rs 32(16+16) instead of unbundling them to be hidden in this fashion.