Cheap General Drakkisath Rogue Deck (Heroic Mode)

Strategy

To defeat this boss cheaply, you will need to take advantage of a quirk in the AI. The AI is very poorly programmed when it comes to dealing with Kel'Thuzad. If you get Kel'Thuzad protected behind a Taunt, the AI will continue to play cards, but will not attack your Taunt, even if they have enough power in play to deal with the rest of your board.

To abuse this strategy, you should mulligan your whole hand for Kel'Thuzad, if you do not get it, Concede and try again. Once you have Kel'Thuzad in your opening hand, you should use other high value cards like Maexxna, Force-Tank MAX, and Sylvanas Windrunner to stall the game for a few turns until you are able to draw a Taunt. Then, it is simply a matter of dropping Kel'Thuzad onto the board, and having it live for a turn.

The AI heavily favours attacking face in this fight, so there are only the 2 copies of Drakkisath's Command that can ruin your plan. The AI is unlikely to use Twisting Nether on a board of a single minion, so this is not a concern.

To increase your chances, apart from the high value minions in the deck, the other cards included are Stealth cards, which can protect your Kel'Thuzad if you are forced to play it early.

Getting these pieces to line up might take you a few attempts, but if you are operating on a budget, this is one of the few ways of completing this fight without access to numerous high rarity Legendary cards.