So Sep's in the money! (5)

I believe the answer is:

pesos

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

'the money' is the definition.
(I've seen this before)

'so sep's' is the wordplay.
'so sep' can be anagrammed to 'PESOS'.
However, I am not clear how this is indicated.

'in' acts as a link.

Can you help me to learn more?

(Other definitions for pesos that I've seen before include "Poses for Mexican coins" , "Poses for Mexican money" , "Mexican monetary units" , "Mexican dollars" .)

I've seen this clue in the Evening Standard.

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