Ransom note is a holodisk in Fallout: New Vegas.
Location
It can be found inside the Bison Steve Hotel in Primm, 2nd floor, on a desk in a room in the southwest of the local map.
Notes
Near the holodisk is a skeletal corpse. Several rooms further there is a locked door with two skeletons, one of which is dead in the bathtub with drugs, another female on the bed. It's most likely a pre-War scene as the note asks for bills, not caps.
Transcript
Mr. Petersen,
If you want to see your wife alive again, bring the cash in small unmarked bills to the Bison Steve on Tuesday.