However if you don't want to make sure you're keeping enough unspendable change around all the time you can always make some 3D printed coins I designed to keep with your game. And with your 3D printed coins you may want a 3D printed version of the original PnP board, also designed by yours truly, for for the game. After that just print out the rules and you're ready to play.
These prints benefit greatly from changing filament colors during the print. Change filament colors on the coins at the 50% mark to give each side a different color. Change filament when printing the board either every 2mm or 6mm (depending on if you're doing the deluxe or card size board) to distinguish the regions.