Nowhere does the Bible say that money is a sin. However, it is the love of money that leads to all kinds of sinful activity.
1Timothy 6:10 [NKJV] For the love of money is a root of all kinds of evil, for which some have strayed from the faith in their greediness, and pierced themselves through with many sorrows.
I hope you have found this helpful.
God bless,
Mike