p0w3r pl4y = power play
Fir3 is fr33 = Fire is free
doumo arigatou gozaimasu = thank you (extra politely)
-sama - suffix for extra politeness, usually towards people of higher social status.
I h4v3 d4 pow3r! Ph33r... = I have da power! Fear...

Largo speaks:
Not that reality matters much in megatokyo, but if you notice, largo was next to the powelines at a step-down transformer, those convert higher voltage to lower (110).