I'm very new to all this and I just, one week ago Monday, obtained a Microsoft Windows-based Nokia Lumia 635 Go Phone. When I first was setting it up a week ago, I had a lot of trouble inputting the correct password from the AT&T modem or router which provides us with WI-FI and land-line phone service. I was using the System Password enscribed on the bottom of the modem instead of the Wireless Network Key as the password into the phone for WI-FI connectivity. It didn't connect the phone to the WI-FI as a result. However, I spent not a little time browsing and listening to music, and as a result, I used a lot of my meager supply of data (5MB) doing this. So, my point is, if you are NOT connected to WI-FI but you think you are, or that it doesn't make much of a difference, you are going to use up a lot of data.
I was doubtful about getting and using a windows-based phone, but my experience with the phone and two technical assistance phone calls (using my land line) has been pretty positive. The phone structure and Apps on the phone seem to be straightforward and well organized. I have learned how to check my data and phone usuage on line using the smart phone and the laptop.
I "favorite" the website www.paygonline.com and check my usuage after spending time on the Go Phone. You just enter your wireless phone number and password and it gives you info on your plans and packages as well as amounts of $ and expiration dates. It also reminds me when the rate plan and data plan are set to auto renew or need some extra cash in the kity from which to draw. (I haven't set up auto refill yet until we get settled on the specific plan we are going to stay with.)
Sorry this has gotten to be so long. Maybe it can be of some use to a beginner using a "smart" Go Phone.
Mike Bailey