After completing the mission "Mister Walpole, I presume?" (Sequence 2 Memory 3 of the main story), open your pause menu (Esc key for PC users), select Progress Tracker, select Sequence 2, Memory 3, and start a replay of that same mission. Play the mission until reaching an optional objective to pickpocket the three Templars. Once at that point, pickpocket the three Templars for an average of 750 - 850 Reales. Once pick-pocketed, quickly pause the game and choose Reload. Reload from last checkpoint. The game will allow you to keep the Reales you earned and pickpocket the Templars again. Repeat the above steps until you have 100,000 or more Reales. This can be done in a few minutes time, and 100,000 can easily cover about 20% of the total game's purchases. Note: The game developers prevent you from farming any more than 100,000 Reales on your person using this tactic, so to maximize profit, don't start farming until you've spent all your previous money to get as much as you can out of it.