Both the amount and types of mana you spend onare taken into account while you're choosing a creature card from your hand. For example, if you spenton, you can choose a creature card with mana cost,,, or, among other possibilities, but not one that costsor one that costs.
Yes. For instance, I paid BB for a hunted horror and it didn´t work. I tried also 1 generic mana for phyrexian dreadnought and BR kroxa. Neither of them worked.Does the mana you're spending on "" include the necessary colored mana to hardcast the spell normally?