I have been tracking few categories of expenses since 2005. This is the update for my Mobile expenses. Below is the chart for per-day amount spent by me 

The chart is pretty much self-explanatory. The two spikes are when I bought
  1. LG RD3330 Candy Bar Phone for Rs. 2400
  2. LG Nexus 4 Phone for Rs. 23,200
Thus, in the last 8 years, I have spent a grand total of ~$800, or 25 cents (Rs. 15.8) per day.