I wouldn’t even speculate as there are too many variables on how they were mailed, the cost of printing etc.
http://www.scribd.com/doc/36935783/Part-1-of-8-Lucas-Daniel-Smith-4th-of-July-Letter-to-Congress
So I suppose it could have added up to ten grand. Or ‘Ten Grand’ may just be a ballpark number instead of $9,273.11.