There are several ways you can get Cash in Star Chef 2:

1) Team Chest - Team works collaboratively to win a Team Chest
2) Completing Chef Journal Chapters
3) Completing Achievements
4) Watching video ads on the billboard next to Supermarket
5) You have a chance of winning Cash on opening Dock Chest from Boat.
6) Spin Wheel

In addition to all that, you can always buy Cash by tapping on the "+" button next to your Cash balance at the top of the screen.