Commas before and after 'too'

I am always hesitating in writing to put commas before and after too, because it sort of encumbers the sentence or unnecessarily interrupts the course of meaning, at least in my eyes. Should it always be used between commas or is there a rule with exceptions that can guide me?

For example, I have no problem of putting a comma before ‘too’ when it ends a sentence:

She did not only buy apples but oranges, too.

But if ‘too’ is in the middle, that’s where my hesitations begin:

His desire is to make sure that the law is applied in our district so that we, too, (or we too) may be protected.