While this is a detective game, it could stand a trainer. You have to balance trying to get interesting fares, along with those that will give clues, the amount you make and the ammount of time in the game.
A money or time trainer might be useful for just experiencing the story without having to worry about that.
Do you have any saves?
Where do they go?
Probably not going down this long story path without saves.
Saves would be best RIGHT AT where you can see money and spend it on fares or something that triggers changes in money. Also if there is a key or screen that quickly shows your money, where that is and how to access it.
best,
Cal