How to add emojis to my message and how much does it cost?

An 'Add emojis' button is available in the campaign composer:

You can also right-click and click on Emoji. Click and choose the desired icon in the drop-down.

Adding emojis does not have an extra cost, however, emojis are Unicode characters, and they reduce the length of 1 SMS from 160 to 70 characters. In addition, each emoji counts as two characters.