I use Battery Doctor.
It has a Switcher Widget that will toggle DATA, SYNC, WIFI, BLUETOOTH, GPS off.
I use it every time I put the phone to sleep. That is how I get greatly extended battery life.
If DATA and WIFI are turned OFF, there is no way apps can talk to the outside world and run up your tab for data chargers.
My habit of turning that stuff off is getting me 3 days minimum..... I have 3 days now and 47% left.... and have had 5 days use once... I'm going to continue this particular use cycle to see how many days I can get out of this battery before it has to be charged.
I have a wireless charger installed, so it is just an exercise for curiosity reasons. I don't use the USB port anymore unless I need to transfer files/pictures to/from the phone to the PC