A lot of balance and care goes into choosing the cost of a card, more than I can express here, but looking for similar effects on existing Magic cards can give you an idea of a fair costfor example, a ramp spell that puts two lands into play ought to cost 4 mana, per Explosive Vegetation
If you don't control an Army, create a 0/0 black Orc Army creature token first.) If you choose a value of 0 for X while you don't control an Army, you will create a 0/0 Orc Army creature token and won't put any counters on it
It then becomes Bloodsworn Knight , a card that has power and toughness equal to the number of creature cards in your graveyard
Total : 121 types 12 cards per pack
Mazes End Everyone knows whats up when Maze's End hits the battlefield
Rinse and repeat as much as you want