If you're on iOS, you can use Metal Zone Schedule
If you're using Android, there is Terra Alarm
Wait for the bear to "walk/dig" in the TunnelBear application. Only then you are connected to the VPN it connects to. When you go in the Google Play Store (when you're connected) it shows you the US content (if you set the TunnelBear region to US).
If this doesn't work (maybe it's your phone or android version) there are plenty of other free VPN applications (CyberGhost for example)