The money gesture, also known as the pay me gesture, is signalled by repeatedly rubbing one's thumb over the tip of the index finger and middle finger. The gesture resembles the act of rubbing coins or bills together and is generally used to indicate financial topic.[1][2]
^Armstrong, Nancy; Wagner, Melissa (2003). Field Guide to Gestures: How to Identify and Interpret Virtually Every Gesture Known to Man. Philadelphia: Quirk Books.