Henry Gale's $20 note in ("Dave").
On the bill a note is written from Henry Gale to Jennifer. The writing, along with the driver's license in the wallet and the fact that corpse was a man, proved that Ben's claim of being Henry Gale was false.
Screencaps show the bill to be a US $20 bill, specifically: SERIES 2004 (therefore introduced into circulation on October 9, 2003 ), serial number EF61363822B. This dates the balloon crash to sometime between October 9, 2003 and the finding of the balloon by Sayid on November 21, 2004.
The message in the note reads as follows: