Well, that is really a play on words. Because deferred adjudication is not a conviction they cannot give you a "fine". However, they can and do charge you a deferred fee that usually is the same or very similar in amount to the fine that would have been charged had you pled guilty and been convicted. With a class C moving violation, a deferred adjudication disposition means that a conviction does not go to Austin to be placed on your driving record.
You will pay court costs and whatever other fee they charge for the privilege of receiving a deferred. The good news is that you will not be convicted of the offense and it will not be reported to DPS.