Automatically insert text to ticket reply

Is there a way to insert a text at the beginning of each email ? We need to insert a text like "please hit reply all when getting back to us" and to repeat this text over and over in each message to the client, until they understand :)

So, is there a way to insert text by default ? Beside the insert signature option, I haven't found anything else. PS: Our company is on a free version now. If you know how to do this for paid version, please advise and we'll consider upgrading.

Thank you !