Never forget to walk away with more than you've brought.
Bobblehead - Barter is a Fallout 3 item, a Vault Boy bobblehead. It permanently improves the Lone Wanderer's Barter skill by 10, to a maximum of 100.
It is found in the Evergreen Mills bazaar, in a dark cave-nook, in the corner of the room to the right of Smiling Jack. Jump over the workbench, and it's on the rightmost shelves.
The bobblehead shows the Vault Boy holding a Nuka-Cola bottle cap, even though the bobbleheads are supposed to have been made before the Great War, when bottle caps were not currency.
Collectable Barter bobblehead available from the Bethesda store.