Resonance of Fate

To make Chapter 6 or later required Combat Scope Betas cost 3,000 Gold, one glass shard, and one scrap of iron. The wandering merchant sells glass shards and iron scraps for 200 and 150 Gold respectively. Combat Scope Betas sell for 4,100 which means there is a profit of 750 per scope multiplied by 999 which is 749,250. The best time to perform this is chapter 6-7 just before the merchant starts wondering why she is always at the Waterless Bridge. In chapter 8 plus, she can be at Forsaken, the Waterless Bridge, or the Righteous Tower. Your best bet then is to get into an enemy counter, run away, and check the location to see if she is there. Time phase changes also change her position. Keep repeating until you have the desired amount of money.