I purchased my first mobile phone when I was 18, and was heavily stung with £40-£50+ bills. Since then I have shyed away from using a phone, managing instead to do well enough with Skype and other tools. However, on the recommendation of a friend, I purchased his HTC desire.
What an incredible difference it has made.
These are the apps that I would recommend. I’ll write a little more about them later, particularly as to how they apply to students. But, for the time being, here they are: