Normally I suggest a shuttle ride to a hotel in Scottsdale, most of the hotels have a rental car desk in their lobby, so you avoid all the extra airport taxes and fees, and trust me, they are substantial-
The breakdown
% of rental price taxes
11.11% airport concession recovery fees
5% vehicle license surcharge
3.25% stadium tax
+ a Trans Priv Tax(???) and additional state sales taxes


Additional Fees
$6 per day customer facility fee (helps pay for the rental car center)
$0.70 per day (maintenance fee for rental car center)
$0.47 per day Energy recovery fee


Bottom line, add an additional 45% to your rental car cost at PHX