Sierra Madre Chip

 is a miscellaneous item in the Fallout: New Vegas add-on Dead Money.

Use
They can be used to purchase items (mostly food items, but chem requisites can be found in the clinic) from Sierra Madre vending machines.

Location
These little chips are found all throughout the Sierra Madre. - in The Villa, many can be found in fountains, whereas in the Sierra Madre Casino, many can be found in cupboards, suitcases etc, most notably, 303 can be found in a suitcase in a room on the Suites level of the casino.