This is a container clue - one word or set of letters goes inside another word to form the answer.
Look for 'overwhelms' as the container indicator. Find a word meaning 'ambassador' that goes inside a word meaning 'that which raises pitch'. The ambassador abbreviation is a short form for 'His Excellency'.
Answer: CHEAPO | HE (His Excellency = ambassador) goes inside CAPO (device that raises pitch on guitar strings), with 'overwhelms' indicating the containment: C-HE-APO = CHEAPO (budget item)