I wanted a cheap legendary deck to get to 4000 trophies with. Below is the deck I used:
Lava Hound: Your tank and main pusher. Try to use when you have an elixir advantage
Balloon: Main damage dealer. This is what goes behind the lava hound to take out his towers.
Inferno Dragon: This you will actually use primarily for defense. This is good against pushing golems, royale giants and opposing hounds. If the balloon and hound are out of sync, you can push with a lava hound and inferno dragon.
Minions: Fantastic behind the lava hound. I usually start out with a Hound + Minion push at the beginning of the game since it is cheap, but still needs to be dealt with.
Skeletons: Used to help burn down Royal Giants, Hogs, Golems and Its a cheap cycling card.
Arrows: To take out his minions. Awesome 3 for 5 elixir trade for his Minion Horde
Fireball: Deals with Elite Barbarians, 3 Muskateers, Wizards and Muskateers.
This deck is straightforward and gets a lot of 3 stars. Let me know if you want me to post game replays.