Complex sentence: Some of the restaurant facilities and furnishings cost a great deal of money and while the restaurant has a relatively slow rate of earning money, the player has the option of spending actual money to purchase in-game money or toxins.
Split into simpler sentences: Some of the restaurant facilities and furnishings cost a great deal of money and the restaurant earns slowly. But the player has the option of using actual money to purchase in-game money or toxins.