There is a glitch that will allow you to get infinite amounts of money.

Play the game until you reach Sequence 2: Memory 3. Once you access it, you can do so at any point throughout the game.

In Sequence 2: Memory 3, play until you find three Templars around a table and get the optional objective “Pickpocket All Templars.”

Pickpocket the three Templars.

Pause the game and choose to reload from your last checkpoint. This will save the money you got, but return you to the point before you pickpocketed them.

Repeat these steps until you have as much money as you want. It will take about 7 minutes to get 35,000 R with this method.