In Gmail , after you click "reply" there should be the textarea box which contains the other person message and where you type your reply into. Above that box are all the rich text formatting options (bold, underline, center, etc) and to the right of that should be a link "Plain text". Clicking that link will put the carrots back for you.

But, I don't seem to see a option to always use plain text in replies.

Hope this helps.