por
Definition
Preposition used to indicate the agent performing an action, equivalent to 'by' in English.
Preposition expressing purpose, cause, or exchange, meaning 'for' or 'because of'.
Preposition denoting means, manner, or duration, translated as 'by', 'with', or 'per'.
Preposition indicating motion through a space or time, akin to 'through' or 'along'.
Examples
Pagué una fortuna por este café que sabe a agua sucia.
I paid a fortune for this coffee that tastes like dirty water.
El perro fue regañado por comerse los zapatos del jefe.
The dog was scolded by eating the boss's shoes.
Viajamos por carreteras secundarias para evitar el tráfico de zombies.
We traveled through back roads to avoid the zombie traffic.
Estudio por las noches porque el día lo paso durmiendo como un vampiro perezoso.
I study at night because I spend the day sleeping like a lazy vampire.