Android: Avoid excessive data usage

APNDroid is one of those free, must-have applications (scan the barcode below to download on your Android phone):

A simple, little program which switches mobile data access on/off by just appending/removing “apndroid” to/from your APN-name. If you mainly work off a wireless network and rarely (but sometimes really need to) use a 3G/Edge/GPRS connection, this saves you the hassle of adding/deleting the APN manually.