A text message marketing services is an SMS message, it is short message that consist of 160 characters. You can write more than 160 characters in a long paragraph SMS to someone, this is usually broke down into several 160 characters SMS and then reassembled back into the paragraph on the other side.

An sms text messaging services can only consist of words and emoji's. For example, if you were sending a picture of your new house and a comment saying 'we just moved in' to your friend on iMessage but you had an option to send it as a 'Text Message', it wouldn't be an SMS in that case. It would be an MMS, an MMS stands for Multimedia Message Service.

text message marketing services that contain pictures or videos, or rich content. An MMS is sent through the internet via your carrier's network, you cannot send them over WiFI. Therefore if you can't iMessage your friend because of lack of Wifi and Cell data, the picture won't send because the MMS does need a connection. 2G connection will send MMS, even if they do not send iMessages.

When you fling an sms marketing services, the message is sent from your phone via the tower to the SMSC (short message center), this is an entity in the cell phone that stores and forwards text messages.

If you are traveling between two states and you are in an area with voice only online messaging service, your text only Message will still get through to your friend's phone as SMS actually travel across the carrier's phone network, the same way fax use go over telephone networks.

... In summary, a single sms message sent cost N4. Thanks.