I went last year and rented an SUV from Alaska Adventure Car Rental. It was like a rent a wreck place just a couple of miles off of airport property. The car lot was not much to look at and the prices have probably gone up some, but I payed $424.56 for 6 days. We fished out of Seward and they said they would send a replacement if anything went wrong. Nothing did, car was clean, worked out OK. They also have an office in Homer and Fairbanks. Looking through old receipts, the phone is 1-877-227-0650. Might be worth asking. Have fun and good luck.
Ron