The developers will tell you that you dont have to spend real money to get anywhere in the game, but, that is not entirely true. There will come a point where you dont have a choice. In one of the "missions", you have to turn a flower into a pigment, however, the only way to get the flower is to fill orders on the board, but, to fill those orders, you need the colored pigments, which you can only get by either using gems you already collected, or, spend real money to buy gems.