That's a great question and you've come to the right place for answers.
iMessge is a great way to stay connected with friends and family. As rcshnoor mentioned, it uses data when sending and receiving iMessages unless you are connected to WiFi. Standard text messages do not use data.
Follow us onTwitter @VZWSupport
My daughter has been using IMessage and tells me that if she turns it off to save data that she cannot send or receive texts to/from other Iphone users. Is that true or is she tellin tales?
It is kind of true because of how Apple has their system set up.
She needs to unsubscribe her number from Apple's iMessage system and not to use it at all anymore. She can go into settings under messaging and turn off iMessage. This SHOULD unsubscribe her number from Apple's system, but Apple is not vigilant in keeping their system up to date to dissuade people from leaving their fold. To help with the completeness of her leaving iMessage in the dust, you should have her text the word "stop" to 48369 after she has turned off iMessage. She should receive a reply that she has been removed.
She MAY still have problems receiving texts from iPhone users, but this will hopefully help. If iPhone users have SMS messages disabled, though, those iPhone users have their settings such that their phone will not send texts except to those using iMessage.
Hopefully this will help. Good luck.
Of course, if she simply turns iMessage back on, this will undo all of these steps. She needs to turn it off and KEEP IT OFF.
I understand your concern, I have been in the same situation as well! This is defintiely true, iMessages need to have data turned on in order to work. They can be turned off, they will simply de deducted from text allowance. However, you can still keep data on and save on usage. Go to Settings>Cellular>Use Cellular Data For: Turn off all the apps you don't want using cellular data. This way you can keep iMessages on but limit data use.
Follow us on Twitter at @VZWSupport