STOP calling it “Costco 3B member.” It’s not a secret tier. It’s not VIP. It’s not a hack. 😅

If you’ve seen “3B” on your receipt (or heard someone say “I’m a 3B member”), here’s the real story in plain English:

That code is on your receipt because the exit door uses it to verify your receipt is valid for .

Yep — the biggest plot twist is this:
You thought it meant you unlocked something.

It actually means Costco is running a simple anti-theft door check.

And once you know that, the whole “receipt check” makes way more sense — including the part everyone laughs about: the employee drawing a dramatic line on your receipt like they’re autographing your groceries. 😂

So what is “3B,” really?

Think of it like a daily door code.

Costco prints a code on receipts that changes from day to day (you might see things like 3B, 2A, 4C

). At the exit, they make sure your receipt matches the day’s code.

Why does that matter? Because some people try to reuse an old receipt on a different day to “walk out” with items they didn’t pay for.

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