Is there a comma between you and too when writing too?

You are correct! There is no comma between "you" and "too" when writing "too."

Here are a few examples:

* "I want to go to the park, too."

* "Can you come with us, too?"

* "He's going to the beach, too."

The word "too" in these cases is an adverb that means "also" or "in addition." It doesn't require a comma before it.