The Windows Store Certification requirements (section 4.5) stipulates that apps doing data transfers must avoido doing large transfers over metered connections (you know, the ones that charge you outrageous amounts of money if you exceed a typically-small transfer limit!). At the same time, getting a device set up on such a network can be time consuming and costly (especially if you exceed the limit).
There is certainly room here for third-party tools to provide a comprehensive solution. At present, within Windows itself, the trick is to use a Wi-Fi connection (not an Ethernet cable), then open up the Settings charm, tap on your network connection near the bottom (see below left, the one that says ‘Nuthatch’), then in the Networks pane that appears (below right), right click the wireless connection and select Set As Metered Connection.
Although this option doesn’t set up data usage properties in a network connection profile, and other things a real metered connection might provide, it will return a networkCostType of fixed which allows you to see how your app responds. YOu can also use the Show estimated data usage menu item (shown above) to watch how much traffic your app generates during its normal operation, and you can reset the counter so that you can take some accurate readings:
It’s also worth noting that Task Manager has a column in its detailed view, on the App history tab, for metered network usage, where you can track your app’s activities.
It’s good to know this as a user, too, as you can see if there are any misbehaving apps you might want to reconfigure or uninstall.