In regards to using Auto Slash I have had good luck with securing lower rental costs thru them in the past and have not had any problems until this trip where I booked the rental car thru Priceline for a car with Alamo on the Big Island and thru Advantage on Maui. Both of these rentals were prepaid thru Priceline. With Alamo, when I returned the car they charged me a $100.00 rent tax surcharge. When I got to Maui I looked at my contract and it states that the rent tax surcharge is included. I called the local number for Kona Alamo and was transferred to someone not local who said she could not help me but would refer the overcharge back to local Kona Alamo to have them contact me. I tried to tell the person checking the car in that the charge was in error but got nowhere and due to time constraints I waited until arrival in Maui to contest. I still don't know the outcome.
With my rental with Advantage on Maui I went to the normal area for rental car pickup and no Advantage van. After inquiring of an airport personnel I was told to go to the center island about 500 yards back past where I had started to wait about 20 minutes for a pickup van that took me about a mile off the airport site to a downtown location where it took about an hour to get a car that was different than the one I had a prepaid reservation. When I got in line there were two people at the counter being waited on and two people in front of me in line. In the wait time, 4 people came in with complaints about the car they had just rented and were asked to come to the front of the line ahead of us that were in line. This I can understand, but there should have been someone to resolve their problems other than the two agents that were there for new arrivals. When I finally got to an agent, a new agent that had opened up a new line, after going thru the sales routine and charging my credit card $200 deposit which he said would be returned to me if the car was returned and everything was in order, he gave me the keys to a car, that, I later found out was different to the one I had reserved and prepaid for, when I got to the car. By this time I was so mad and frustrated that I got into the car to go back to the airport to pick up my wife and luggage rather than go back in and go thru the hassle all over again. I am still in the smaller SUV and am to return it back to Advantage tomorrow. We will see what happens then.
My point is watch out for these rental agencies. I don't know if these were honest mistakes or something else to make more profit. When I was at the Advantage counter I felt like I was in a 3rd. world country like Mexico instead of the United States.