I thought I knew everything (well okay not really ) until I found a TA thread that mentioned the discount codes at Islandair.com (see link below for codes)

http://www.islandair.com/special-offers/current-offers

Much to my surprise the codes beat all my other discounts, even the well regarded costco codes. Here's the math for a one week Maui rental (intermediate):

Hertz $320 all-in with AAA discount
Alamo $238 ai with Costco code
Avis $228 ai with island air code
Budget $196 ai with island air code

The taxes and fees are absurd, now about 25-35% of the price.

Note also that Advantage usually has the best rates quoted on orbitz, etc. but some horror stories have been reported on TA for this location, so maybe not worth the price.