I'm assuming you are asking if either situation is a cost?
The first one is not. Prisma sends the monster to the grave as part of his effect.
The second one is not either.
"If an effect chained to this card causes you to have no "Neo-Spacian" cards in your hand or Deck, this card's effect ("Draw 2 cards.") does not resolve."
That means the cards getting sent are sent at resolution of the effect. So therefore, not a cost.
EDIT: Here's a link to the rulings for C cards on UDE's site to lookup the above ruling
http://entertainment.upperdeck.com/yugioh/en/gameplay/faqs/cardfaqs/default.aspx?first=C&last=C
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