Should you give your zip code?
It doesn’t seem relevant, you’re just there to buy a pair of socks and it really doesn’t seem harmful. Why do stores do it? The answer is marketing.
When a store has both your name, usually from the credit card you’ve just used and your ZIP code, it can find more of your personal information, such as your mailing address, phone number, and records of what you’ve been buying.
There are people who deal in this data, who can use your name and ZIP to dig up more identifying information. Asking for your ZIP is like asking for your home address. Now you’ve got the junkmail coming.
Sometimes, retailers will tell you they need your ZIP code to complete the sale. Don’t believe it. They can’t force you to turn that over.
If you’re paying with account maintain some privacy, you can simply say no to sharing your ZIP.
There is an exception: gas stations. Sometimes the pump asks for your ZIP when you’re using a card. That’s to stop a thief who’s stolen a card and wants to see if it’s still working without having to go face to face with some clerk.