What happens if a cop ask you for money, so you can get out of a crime? What should you do ?

In my experience a cop will not ask you for money so you can get out of a crime.  If a cop did ask you for money I would not give him any, because there is a chance you would be charged with an additional offense and it would be your word against his.  Also remember to remain silent, you do not have to answer police questions other than providing your identification.