I am flying to Miami from South America this month with my family (my wife and my baby of 5 months) and made a reservation of a Minivan (Hertz). My intention is to buy a child seat (USD 150) on Amazon and send it to the Hotel (in Sunny Isles).

My idea was to rent the child seat 1 day with Hertz, so I can return it the next day, but they only offer the whole period rent (10 days; USD 90).

Is there a different solution I am not seeing?