I’m honestly not sure if someone else has found this method or not, so if I’m “stealing” anyone’s thing please let me know.
This is BY FAR the absolute fastest way to earn money in this DLC, you can net the MAX out which is 99,999$ and it only takes about 10 minutes.
-What you need: Possession Vigor, any Round that has a Motorized Patriot on it, and two automatic machine guns (preferably the machine gun with upgraded clip and crank gun)
Okay so go ahead and start up a Round with a Moterized Patriot on it and bring the weapons I noted. Go ahead and kill every single enemy EXCEPT the Patriot. Once the Patriot is the only enemy left, hit him with the Possession Vigor and quickly run behind him and start to unload on the ‘Gear’ on his back, every single time you hit the gear it will automatically give you cash for doing so. Simply continue to do this either until the Patriot barely has any health left, or you run out of ammo. Once that happens let the Patriot kill you and respawn (the continue and forfeit leaderboard stats option). When you respawn it will only be the Patriot again, and he will have full health, your ammo with be replenished, and you keep all the money you already owned.
NOTE: The farther into the DLC you do this, the more money you will earn per hit. I did it on the 3rd map, and was earning 69$ every single time I shot the gear. But even if you do it on the first map, you will still be earning money WAY faster than any other method or even playing legit.
Not only will this provide you with enough $ to buy all the Art, you will be able to buy ALL the weapon upgrades and Vigor upgrades right away thus spending way less time on this DLC.