Originally Posted by jackal

Generally a bad idea to walk up without a reservation--rates are usually (not always, but usually) significantly higher.

If you're picky about your cars, make a reservation at a rate that appeals to you in a car size you like and then go out and look at that company's cars. You can then ask for a specific car from the rental agent.

Conversely, if you're not picky about your cars, just go straight to the rental counter--no need to detour through the lot first.

But either way, have a reservation before showing up. Someone I know paid $250 for a three-day rental from Hertz on a walkup rental last night at ATL. The same car was available for the same period online from Hertz for $150 ($120 after applying a CDP and PC). (National was even cheaper: $80 with a Contract ID and coupon.)