If you do, that creature gains first strike until end of turn and must be blocked thus turn if able
Similarly, you can't pay a cost that includes the payment of any amount of life other than 0 life
Whereas Izzet Lessons makes this work using non-creature spells, this deck goes the more traditional route, with lots of cheap threats that care about card draw, such as Tiger Seal, Marauding Mako, Fear of Missing Out, and Duelist of the Mind
It would be easy to add many more cards to this tier, but I have deliberately aimed to be selective here in order to show off the cards I actually think are strong, rather than cards that will see play as a 1-of or in some fringe deck
Each spell with tiered has a base cost as well as multiple modes, each with their own additional costs