Padraica Yatsenko

If you're concerned about taking cash that doesn't belong to you (even though it was in error - some people would say take it and run, but some would say it would be nice if you gave it back) you can look back in your Transaction History (it's in the dropdown menu when you login at secondlife.com) and see who it was who gave you the money. Send them a notecard inworld explaining the situation and see if they want their money back. If they don't bother getting back, you can return it or keep it - it's up to you.