AVIS is the rental place we used. Yes, that is an expensive rate, but compared to 5 people on the shuttle @ $125 each it was a bargin. That's why I said you would have to do the math for your situation. BUT even if its just the two of you, its almost a wash and then you can do your own sight seeing and take your time on the way to Anchorage. If you figure in the cost of an excursion in Anchorage and then being dropped off at the airport hours early, the cost is not that out of line.
We quickly found out that the cost of an Alaskan cruise are 3 to 4 times the costs of a Caribbean cruise...
I'm sorry I don't have any other suggestions.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007