Clue: In acerbic manner, money invested in presidential coinage? (8)
Answer: BITINGLY
Explanation: Definition: In acerbic 
An envelope ('invested in') of TIN ('money') in BIGLY ('presidential coinage?' – a well-deserved question mark. The word is associated with Trump, but has a history from well before his time; further, , its usage in the first 2016 presidential debate is a mis-hearing of big-league).