Going to Miami from Toronto for 3.5 days with my girlfriend

We will be in Miami from March 24th to the 27th z the .5 of a day is accounting for time lost travelling. We have a decent itinerary so far, boat tour and Miami Heat game. We plan to visit little Havana on the first day we arrive. Ocean drive and south beach of course. Any other suggestions are welcomed as we’re trying to find different cool and cheap things to do as we do have a budget. We would make an exception of going over budget to go to a nightclub but it seems that most are closed during the week.