Free gold may be earned in-game by Completing 'Daily Goals' and earning trophies.

Watching videos and participating in Special Offers can earn free gold.  In the Bank screen ,tap the button in the lower left that says "free Gold."  Note that there is a limit to how many videos one can watch in a day.

For free supplies, you can ask your Facebook friends who play Cooking Dash too.  In the bank, tap the grocery bag icon and at the bottom, tap the button  that says "Ask Friends."