Car rental prices might decrease over time as the rental getting closer to its due date.
I encountered it when booked a car rental, waited for about a month, cancelled and then re-booked again.
I rented from https://www.booking.com/cars
These are the rental prices over the months before the rental due date:
- $547.73 (first price) - cancelled
- $502.27 - cancelled
- $475.10 - cancelled
- $439.86 - final price
I assume outside of an airport is cheaper