astronomical
mod. extremely expensive; of any very high figure.The prices here are astronomical!The market indexes have all reached astronomical heights for the second time.
jillion
n. an enormous, indefinite number.I've got a jillion things to tell you.This car cost me about a jillion bucks.
skillion
n. an imaginary enormous number.I have a skillion reasons why I won't marry you.About a skillion people are running in the marathon.