The most common and most likely answer to this crossword clue is the 7 plus 5 letter word FOLDING MONEY
F
O
L
D
I
N
G
M
O
N
E
Y
Buddy explains!

The straight part
We know that "notes" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case notes = folding money.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.