In Sunday's Washington Post, Christopher Elliot wrote about the large discrepancy between airport car rental costs, which include all kinds of taxes and concession fees, and rentals downtown, even from the same rental company.  These fees can add up to half the final cost of your rental, and can be avoided if you make your way downtown and rent there.  But this can be inconvenient, and in some places, the cost of additional transportation can wipe out the savings.  One way to increase the savings and convenience is to rent one-way, picking up downtown, and dropping off at the airport — the fees are only added to cars picked up at airport locations.  But Chris missed my favorite trick:  rent at the airport hotel.  Many large airports, like Los Angeles, have car rental counters at their big hotels.  Rent from Hertz LAX, you pay the airport concession fees and taxes.  Rent from the Hertz counter at the Hilton LAX, and you save!  And you can take the Hilton's free shuttle to and from the airport!