How about Standard?

[DylanW18]

I guess I'll consider the game a draw

[IntoFire]

Wait! I'm still here!

[IntoFire]

Draw.
{Mountain}
Cast a {Hypersonic Dragon} and three {Dynacharges}.

[DylanW18]

You can't? The mana requirement for that is {3}{R}{R}{R}{R}{U}. The {Goblin Electromancer} only decreases colorless mana costs. The {Dynacharges} aren't just free

[IntoFire]

Check the ruling section. An article there says I can.

[IntoFire]

You can't? The mana requirement for that is {3}{R}{R}{R}{R}{U}. The {Goblin Electromancer} only decreases colorless mana costs. The {Dynacharges} aren't just free

Plus, I'm only casting the {Dynacharge}s on the Dragon.I'm not casting them on anything else.

[Anoobass]

Check the ruling section. An article there says I can.

Please check the ruling on the card:


Rulings

10/1/2012   Two Goblin Electromancers will make instant and sorcery spells you cast cost {2} less to cast, and so on.

10/1/2012   Goblin Electromancer can't reduce the colored mana requirement of an instant or sorcery spell.
This^

10/1/2012   If there are additional costs to cast a spell, such as a kicker cost or a cost imposed by another effect (such as the one imposed by Thalia, Guardian of Thraben's ability), apply those increases before applying cost reductions.

10/1/2012   Goblin Electromancer can reduce alternative costs such as overload costs.
Because of your 2 electromancers this^ makes the overload cost the same as regular cost.

[DylanW18]

Thank you Anoobass

[Mattao19]

Ya IntoFire is 1 mana short

[IntoFire]

Oops,I miss calculated.I can only afford 2 {Dynacharge}s can't ? If that's the case.I'll just cast two.

[DylanW18]

You had all 4 {Dynacharges} in one game?

[IntoFire]

Well, yes.