Extra fee (9)
I believe the answer is:
surcharge
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">extra fee</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for surcharge that I've seen before include "extra amount" , "Excess fee" , "More to pay" , "Additional sum demanded" , "additional amount" .)