Write a program or app or site that allows that. It will need a link to your database that contains the stock of the product in different locations, so it's a two part project: (1) write the user interface, (2) write the back-end.
If you can't do it all yourself, you might need to hire programmers to do it for you. For #2 you need the cooperation of the database owner also.
How to allow the users to check the availability of the product in any desired area using zipcode?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic