Restaurant City: Free Sugar and Chili says "Drink Me" Up
While it's doable, gathering those 40 will take awhile. Pineapple and Chili are helped by being freely available on the gifts page, but you'll need people to send 'em to you. And Sugar can be grow on your own, but the garden's output is random. That leaves Water as the scarcest and most desired ingredient.
Right now, for a 24-hr period, two of those ingredients can be gotten for free.
Note: All links below will launch the game. You only need to keep the game window open for a few seconds to accept your free item.
FREE Sugar, available 24 hours only: http://bit.ly/beA3BU
FREE Chili, available 24 hours only: http://bit.ly/c9ghx9