That's what bargain is all about: sacrifice an artifact, enchantment, or token as you cast a spell with bargain, and in turn, receive a more powerful effect
Not only is this the best use of red mana in the ramp deck it is a card that doesn't hurt you much at all should you not be able to fix your red
Dont forget planeswalkers like Ob Nixilis, the Adversary
Going by common creatures, this is enough to remove everything except for Balamb T-Rexaur, Iron Giant, and a Gigantoad with 7+ lands out
Creature - Human Soldier Color tag templates(None) Creeping Bloodsucker At the beginning of your upkeep, this creature deals 1 damage to each opponent
So, if you only have a Primalcrux, it is a 6/6 because it has 6 Green mana symbols