Hey - Try the following in their order
1. Clear cache and retry - Settings > Apps > All > Play Store > Clear cache...confirm
2. Clear data and retry - ... > Play Store > Clear data... confirm
3. Uninstall updates and retry - ... > Play Store > Uninstall updates > ... confirm
4. Edit. Remove your Google account from your device, restart your device, add your Google account again and restart your device again.
Let us know should there still be issues.