A few practical ways to lower the total cost.
Booking well in advance, avoiding airport pickup surcharges by picking up in town instead, and comparing total price (not just daily rate) across a few providers are the most reliable ways to reduce cost. Loyalty programs and certain credit cards also sometimes unlock discounts or waived fees.
Renting for a slightly longer period sometimes works out cheaper per day than a short rental, since weekly rates are often discounted compared to daily rates stacked together.