Budget - one-way rentals not always sky-high ?

I need to make a one-way rental from PHX (airport) to Flagstaff AZ. If I return to the FLG airport, it's quite steep $500 or so (for 4 days), but if I return to an in-town location, the price drops to $200+.

Seems very peculiar (thinking the old adage "if it sounds too good to be true, it probably is"). I know frequently it's cheaper when you pickup at an off-airport location (saving the various airport-related fees), but that's not the case here. Another explanation is, I've heard sometimes one-way rentals do not have a steep dropoff fee, presumably when they need more cars in a certain location. But since the FLG airport and downtown locations are about a 10min drive apart, I can't see that's what happening.

I guess I just fear that when I pickup or dropoff the car, they'll go "well, of course the one-way dropoff fee has to be added". In which case, if I can't get resolution at the counter, I just pay it, and dispute the VISA charge, with my confirmation email in hand. Maybe I worry too much ...

Yeah, you're worrying too much. If you make the reservation online and the quoted price is $200 for the off-airport location, they will honor it, no sweat. Your reservations should also indicate the pickup and drop off location plus any "one-way drop off" fee if any. Just make sure those are correct.

The best words on your confirmation: "This rate is guaranteed."

The best words on your confirmation: "This rate is guaranteed."
Actually, mine says "my confirmed rate", but close enough.

Another source of paranoia is that they'll want credentials for my coupon code (U204720) but folks in the massive sticky thread seem to say it's not a problem with that code.

Sometimes I worry that I worry too much ... Thanks for the re-assurances, folks.