Invoice in pouch-like holder, with penny change (6)
I believe the answer is:
docket
'invoice' is the definition.
(document listing a package's contents)
I don't understand the remainder of the clue.
(Other definitions for docket that I've seen before include "Voucher" , "Label or note that comes with a package" , "Certificate, label" , "Consignment paperwork" , "Counterfoil" .)