Each level has its own economy. Money won't be transferred between prisons.
The Government was looking for a competitive manager able to make prisons grow starting from scratch, and we are sure that you will do a great job. 
We will forward your feedback regarding this feature to the team so they can take it into consideration, but please take in mind that the main point of the game is to advance into more challenging prisons, so this money shouldn't be so relevant. With your previous experience, you will be able to succeed at higher levels!