Is it a half a gig on you wifi or a half a gig of cellular data?
In any case take launch the Data Sense app, swipe to Usage and see what app is consuming a lot of wifi/cellular data.
Seeing usage t hat high can definitely be alarming Aus. I would be concerned also. Setting up your phone for the first time may consume data that you were not expecting. Downloading apps, restoring contacts, setting up email, and social site may have used some of the data in question. Now that you have your new phone up and running, try ensuring that all apps are closed when you're not using them. Know that streaming music, movies, and games will also consume data. If usage continues to stay high, please let us know so that we can investigate. Just as a reminder, you can also change your plan at anytime http://bit.ly/xdDajD . Monitor usage via #Data on your phone, My-Verizon online and usage alerts. I hope this information was helpful.
I had/have this issue too., my data plan is sharde with 4 others and my droid never got close to running us over out GB, but this phone just drains the data and i feel like I am 80% on wifi usually. I noticed that when I open my wifi connectivity, it will say 'searching", then if its one I use alot it will say "connnecting" instead oj just automatically connecting.
KinquanaH_VZW has very good suggestions, but I'd like to elaborate on one that might be helpful to close apps when you're not using them.
Go to Settings, and swipe across to "applications". Select "background tasks" and block whatever you can. Of course, you might find that this will affect the behavior of an app in a way that you'll have an unacceptable startup time, or be annoyed at always starting over at the front page when you are momentarily away, so you might have to tweak some apps back into being "allowed".
You also could possibly have some unintentional but high bandwidth settings, like Photos.Settings.AutoUpload.
Previous to my Nokia Lumia 822, I split my data between WP6.5 and WP7 devices basically sharing the same data plan. I never exceeded 400MB/month and was almost always under 250MB. After one month with WP8, and I am at 905MB even though I access all the wifi I have available to me, as before.
On WP8, Data Sense shows me where I've used it, but I'm still not sure what behavior I've changed. I remember setting up my email to check by itself, and these were always "Manual" before. All my email is about 110MB/905MB. I don't have statistics that break it down like Data Sense for prior months.
The top use is 152MB/905MB for streaming media. I don't recall how I got to such a high number, but perhaps I haven't been conscious of all the times I've downloaded media outside of wifi. It's possible the 93MB/905MB for Internet Explorer is because I'm getting more web pages than whatever "clipped" versions WP6.5 had. The 68MB/905MB for app downloads are for things I wasn't patient enough to get when I had wifi. These are my top three uses in Data Sense.