Bundles of notes with bills (4)

I believe the answer is:

wads

I'm a little stuck... Click here to teach me more about this clue!

'bundles of notes' is the definition.
'wads' can be an answer for 'bundles' (I have seen 'Bundles of papers' mean 'wads' so perhaps 'bundles' could also mean 'wads'). I am unsure of the 'of notes' bit.

'with bills' is the wordplay.
'with' becomes 'w' (abbreviation).
'bills' becomes 'ads' (I can't justify this - if you can you should give a lot more credence to this answer).
'w'+'ads'='WADS'

Can you help me to learn more?

(Another definition for wads that I've seen is " Bundles of papers".)

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.