Puzzle 39 Solution

Note that it was a trip to USA. The US $100 note is a portrait of Benjamin (Franklin), the US $10 note is a portrait of Alexander (Hamilton) and the US $2 note is a portrait of Thomas (Jefferson). So Chork in fact had US $112 with him which was just enough for him to get 4 spy kits. Thus one kit costs $28.

Answer: $28