Forum:Cost to activated spell and trap card

Do you pay the cost before the spell or trap card is face-up on the field? I am asking this because in the video game yu-gi-oh WC 2007 the cost is payed when the spell or trap card is face-up on the field however the chain is only comfirmed when the cost is already payed.96.44.82.53 (talk) 12:22, March 18, 2011 (UTC)