Both AutoSlash and Costco Travel promise the same thing — a lower price on the car rental you were already going to book — but they get there in completely different ways. AutoSlash is a free rebooking-alert service that layers on top of a reservation you make directly with a rental brand. Costco Travel is a private booking channel that only Costco members can use in the first place. Which one actually saves you more money depends on whether you already have a Costco membership and how much effort you’re willing to put in.
How AutoSlash Works
AutoSlash doesn’t book anything for you upfront. You either book a fully cancellable rental directly with a company like Hertz, Avis, Budget, Enterprise, National, or Alamo, or you let AutoSlash search for the best available rate across those brands at your dates and location. From there, AutoSlash keeps watching the price. If the rate for your exact car class, dates, and location drops — because of a new coupon code, a loyalty discount, or just market pricing — AutoSlash emails you and lets you rebook at the lower rate.
The rebooking itself isn’t automatic in the sense of silently swapping your reservation. It creates a new reservation at the lower price, and you then cancel your old one. Because most rental reservations are free to cancel up until a day or two before pickup, this costs nothing and there’s no real downside to checking back. AutoSlash is free to use and doesn’t take a cut of your rental — it earns commissions from the rental brands instead.
How Costco Travel Works
Costco Travel is different in kind, not just in mechanism. It’s a private travel-agency-style portal that only shows rates from a short list of partner brands — currently Alamo, Avis, Budget, and Enterprise — and every price already has Costco’s negotiated member discount and best available coupon baked in. You need an active Costco membership (Gold Star membership starts at around $65/year) to book, and the primary driver on the reservation has to be the member and show their card at the counter.
In exchange, Costco Travel bundles in perks that normally cost extra: a free additional driver, and in many locations, waived young-driver fees. Executive members also earn a 2% annual reward on what they spend through Costco Travel. Cancellation policies on Costco Travel bookings are generally flexible, similar to booking directly with the brand.
AutoSlash vs Costco Travel: Side-by-Side
| Factor | AutoSlash | Costco Travel |
|---|---|---|
| Membership required | No — free for anyone | Yes — active Costco membership |
| Brands covered | Hertz, Avis, Budget, Enterprise, National, Alamo, and more | Alamo, Avis, Budget, Enterprise only |
| How savings happen | Automatic price-drop monitoring + manual rebook | Pre-applied member discount + best coupon at time of booking |
| Extra perks | None built in — pure price tracking | Free additional driver, waived young-driver fee (varies by location), 2% Executive reward |
| Effort required | Check email, rebook, cancel old reservation | Book once, discount is already applied |
Which One Should You Use?
If you’re already a Costco member, the smart move is to do both. Search Costco Travel first since the member rate and driver perks are often hard to beat outright, then run that same reservation’s dates and car class through AutoSlash to see if a non-Costco rate — or a better coupon elsewhere — undercuts it. AutoSlash works on top of a directly-booked reservation, so if Costco Travel doesn’t have the best price at your location, book directly with the cheapest brand and let AutoSlash keep watching it.
If you’re not a Costco member and don’t want to pay for one just for car rentals, AutoSlash is the easier default — it’s free, requires no commitment, and covers more brands. The math on a Costco membership only works out if you’re already using Costco for groceries, gas, or other travel bookings where the annual fee pays for itself elsewhere.
FAQ
Does AutoSlash cost anything? No, AutoSlash is completely free for renters. It makes money through referral commissions from the rental brands, not from you.
Can I use AutoSlash on a Costco Travel booking? No — AutoSlash monitors and rebooks reservations made directly with a rental brand, not third-party bookings made through Costco Travel’s private portal.
Is Costco Travel actually cheaper than booking directly? Usually, yes, because the displayed price already includes Costco’s negotiated rate plus the best applicable coupon — but the exact savings vary by location, dates, and car class, so it’s worth comparing against a direct AutoSlash-tracked booking before you commit.
What happens if AutoSlash never finds a lower rate? Nothing changes — you keep your original reservation at the original price. There’s no penalty for using the service and no result if the market doesn’t move.
Verdict
Costco Travel wins on baked-in savings and driver perks if you’re already a member; AutoSlash wins on flexibility and brand coverage for everyone else. The two aren’t actually competitors — they solve different parts of the same problem, and using both costs nothing but a few extra minutes of comparison shopping.
