Simple, go for weekly rates.
Car rental companies will usually reward longer term rentals with a discounted daily rate. These are what they call weekly rates which, depending on the car rental company, is defined as being at least a 4 or 5-day rental period.
Instead of paying, hypothetically, $60/day for your rental, on a weekly rate, the rental company may charge you only $30/day. The interesting thing is that because of this pricing system, sometimes a 5-day rental can come out to be cheaper than a 3-day rental.
That’s why we recommend always doing your homework and comparing a few different rental periods before settling on which best suits your needs. It may just save you some extra spending money for your trip.