Reader Brian B. offers a good reminder:

Needed minivan + different city return… ended up with Budget @ [$600+] + $350 one-way fee!

…I fill out Autoslash’s form. I forget about it. 10 days later (4 days before my trip) i get a response.

Mid-size SUV @ $450 (instead of $950 for a minivan). Wow! Book immediately.

Two more emails and the price is $410. I would not have re-checked Avis four days before the trip. This saved me $600! But yet service remains shady looking. But I now love those guys more than usual.

I first covered Autoslash.com in June of 2010.

Back then there were two things this free website would do for you:

• They would automatically test and apply coupons and discount codes to get you the lowest rate on your vehicle at booking
  
• They would keep searching after you booked your car in order to find you better prices. Rental car prices change all the time, especially as time passes and the rental date nears, if rental companies have unbooked inventory

The biggest savings came from this second technique. Most people make car reservations and then leave things alone, but prices do drop, often significantly. I’ve seen folks report saving several hundred dollars on longer rentals, and reducing prices by more than half, as in Brian’s case above.

Testing discount codes, though really angered the rental companies. (It’s also gotten them unfairly chastised by so-called consumer advocates.) And one by one those companies stopped letting Autoslash make reservations.

Even though you can’t really book rental cars in a useful way on the Autoslash website, they’re still invaluable — most people don’t know it, though.

They’re still even one of the most useful travel websites and a key component of the 12 ways to save money on rental cars.

See, you just have to book your rental car reservation somewhere else. Then you enter your confirmation number on the Autoslash website. They will keep scouring for lower prices for you. They’ll email you when they find one, and can get you re-booked with the savings. You don’t make the initial reservation with them, that’s all that has changed. You still get the savings from changing prices. And that’s always been the best part of the service anyway!

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