Learn Portuguese (Portugal): Eu passo sempre por aqui.

Pelo and pela are made by combining por with the definite articles o or a (the). Since aqui means "here" and doesn't use "the", we use the basic preposition por on its own.

Does por mean "through" in this sentence?

Yes! While por often translates to "for" or "by", when used with a verb of movement like passar (to pass), it usually means "through" or "by". Passar por is a very common phrase meaning "to pass through" or "to pass by" a place.

Why does sempre come after the verb? In English we say "I always pass".

In Portuguese, words that tell us how often something happens, like sempre (always), usually go right after the verb they describe. So, "I always pass" translates to passo sempre instead of the other way around.

Do I need to say the eu?

No, you can easily drop it and just say passo sempre por aqui. Because the verb ending in passo tells us exactly who is doing the action (I), the word eu is optional.