how to insert values into cells in excel programatically C#

Hi there

Im trying to pass 8 string values in to a row in an excel spreadsheet and then be able to select that row all programmatically using C#. I am using a Windows Service with a file system watcher that is constantly monitoring a directory for a file to be added once the file is added it needs to extract the file contents in to object properties and then write them to an excel sheet. Would anyone have any idea how to do this without having to pay for any additional excel extensions? Any help would be much appreciated.

Thanks