Uncommon bills (4)
I believe the answer is:
twos
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">uncommon bills</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for twos that I've seen before include "Deuces" , "Couples" , "Pairs" .)