Printable Bank Book for each individual student - correlates with product - Classroom Economy Job Descriptions
Bankers are to fill in bank book for their "clients" (or students can always fill in their own)
Banker's signature is either assigned banker or teacher.
In my Year 6 classroom, money is just hypothetical. They get paid each week but also receive money for things I notice within the classroom - positive reinforcement.
I also say a stamp is equivalent to $50 and a sticker is $100!