travel advice for broke american college students

hi! i am currently planning a trip with my boyfriend to stay in montreal for 3 nights. we're staying in an airbnb in downtown, and are trying to have as much fun with as little money spent possible. we're interested in the nightlife in the city, what are your favorite places to grab a drink? or favorite club? additionally, are there any little to no cost activities that you enjoy to do? this will be my first time out of my country and i am very excited to explore your city !! thank you for any and all guidance