Costco Travel has great rental car deals. But sometimes the best deal on an itinerary comes long after you've booked. Power users know that you can save a lot of money—hundreds of dollars on some itineraries—by rerunning your search every day and rebooking when prices drop.

But that's an annoying waste of time.

AutoSpot checks for price changes so you don't have to. When it finds a deal, you can cancel with Costco Travel for free and rebook to get the lower price.