2017-03-14 : If Thornscape Battlemage is put onto the battlefield as the result of a spell or ability, there’s no opportunity to kick it.

2017-03-14 : Kicker costs don’t change a spell’s mana cost or mana value.

2017-03-14 : You can pay any particular kicker cost only once. You can’t pay it multiple times to get multiples of either triggered ability.

2017-03-14 : You choose whether to kick a spell as you cast it, and you pay that much along with the spell’s mana cost at the same time. Kicking a spell is always optional.