How long will 3gb last me on the internet?

[john]

I work in mobile telecom's. Most of my customers which browse facebook, check the news, send & receive emails, download applications and play the odd youtube video get along just fine with only 1gb of data a month. If your using instagram you will be uploading pictures so that shouldn't be included(however check this as some networks are changing the rules as uploading data becomes more common and is congesting the networks).

The galaxy S3 has the option to display full webpages(as you would see on your home pc) or the option to prioritise mobile web display first. I would recommend the latter.

p.s make sure to set the wi-fi as priority

The industry average is far less data than your getting so you should be fine as long as you stay away from data intensive applications like video and audio streaming.