What stores sell 5th avenue candy bars?

Unfortunately, "5th Avenue" candy bars are not a real thing. There's no known candy bar with that name. It's possible you're thinking of another candy bar or have misremembered the name.

To help you find the candy bar you're looking for, could you provide more information? Perhaps:

* Describe the candy bar: What kind of chocolate is it? What are the fillings or toppings?

* Where did you see it: Was it in a store, online, or in a movie/show?

* What's the brand name?: Is it a well-known brand, or a smaller, local one?

Once I have more details, I can help you track it down!