### Clue: Cost of this unknown to leader in monied class? (4)
### Answer: MILK 
 ### Explanation: Definition: Cost of this unknown to leader in monied class
  M(initial letter of,leader in "monied") + ILK(a class,type,set of items). 
Answer: Reference to the mini-theme with the full quote "…are two posh boys who don't know the price of milk, and are arrogant …."  An excellent clue, great surface and a WIWD(wordplay intertwined with definition) clue.  My last one in and my first COD.