1000 zombies attacking Toltyn = 280000 damage
100 zombies attacking Toltyn = 28000 damage
Price to go from 900 to 1000 zombies = 323.579 oct
Price to go from 0 to 100 zombies = less than 3 million
It's cheaper to beat the campaign with less monsters.
It takes about 200000 zombies to conquer Totlyn. So you could conquer it for about 6 billion bucks and make a huge profit. Just depends on how much time you want to waste.
Ha.