Is there a more affordable way to send short messages?

It's simple. Change your card to a mobile dynamic area and send a lot of text messages. Then send a group message to tell all your relatives and friends that you have changed your number. It's convenient and easy to send text messages, but I don't know what mobile phone you are using. Generally, a mobile phone with a data cable can be connected to a computer. Typing on a computer keyboard is much faster than typing on a mobile phone keyboard, right?