Hello, With 300MB of data exchange to check your emails, even if they occasionally contain images, 300MB is more than enough. I advise you, however, to update your applications over Wi-Fi when you are at home.
300 MB of data exchange is sufficient for light web activity on a phone. App updates and checking emails (if they are not too many and do not contain images) The size of the allowed exchanges has no impact on telephony functions (calls, SMS)