Text (EX): For each creature, that creature's controller pays {1} or sacrifices a permanent.
At the beginning of the resolution, each player counts up the number of creatures they control, then they make the required number of payments and/or sacrifices. The active player announces their choices first followed by the other players, but all the sacrifices are done at the same time. [WotC Rules Team 1998/07/01] Because of this, you cannot sacrifice one creature in order to pay for another and thereby avoid payment for the first. [Barclay 1998/06/10]
You can choose to pay some mana and sacrifice some permanents if you have more than one creature. [Barclay 1998/06/10]
You can play mana abilities during the resolution if you decide to pay mana. [D'Angelo 1999/06/01]
