You can actually clear two levels a day without having spend too much money. This works best after completing Level 1076 of Chapter 55.
Here's how to do it after completing Level 1076
Have a Gold Hat in reserve.
By completing Level 1076 of Chapter 55, (you can do this in 8 moves or less) and earning your Brown Hat immediately go to Chapter 1, Level 1 and play until you are within rage of earning a Blue Hat. Can take 3-4 times. Always take out the blue, yellow and red bubbles at the top and you will clear the level quickly.
Immediately go back to Level 1076 and earn the Blue Hat, then go back to Chapter 1 Level 1 and play until you are close to earning the Gold Hat. Usually 4-5 times. Again, take out the blue, yellow and red bubbles at the top and you will clear the level quickly.
Hit the picture frame at the bottom of the screen (middle button) and then the yellow arrow. It will instantly take you to where you previous left off in your game.
Purchase Leo's 10x Star bubbles for 50 stardust and start playing by using the Gold Hat first.
On the lower Chapter games you will easily clear most levels with a minimal use of gold bars or boosters.
Once the Level is cleared. Immediately logout and log back in. You will still have access to Leo's 10x bubbles for about 24-21 minutes.
Go to Chapter 55 Level 1076 and earn another Brown Hat and then go to Chapter 1 Level 1 and repeat the process outlines in steps 2-4. You will have 6-9 minutes left to clear the next level.
Note, sometimes you will earn an additional Gold Hat which you may not have to use until the next Level or you may need the new Gold hat to finish the current Level.
If you use both Gold Hats, you can always logout and log back in to earn another Gold Hat. Know that by using this method you will not burn up any lives.
Either way, you can clear up to 2 Levels every 4 hours after Leo's 10x recovers.
Enjoy and hope this helps you further your game through Stella's world.