You will never win any money. They will either reset your progress before you can cash out, or just not let you cash out at all.

While the game is mostly based on luck, chips dropped through the middle of the top are statistically the most likely to win you the big bucks. Try inserting the chip 3 or 4 spaces away from the center. As an alternative, consider dropping your chips 3-4 spaces to either the left or right of the center entry slot.