I would not b other with data use at all not even email. I notice on my BB data transmissions even when there are no apps running that use data. I'd assume that overtime those tiny transmission will add up and there's no telling what that total would be. I don't know how much email you will be sending and receiving but I'd be concerned at how much cost you'd end up with. The only for sure way of preventing any data usage except when you want to use data for something is to turn off data services in the manage connections.
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