Probably unlikely any charge. But the one with your CC info you might want to cancel to be sure.

I'f you're staying on the strip IMO a car is more hassle than it's worth. Parking is a hassle not to mention traffic. You can take several cabs for the same money and less time.

If you're staying mid strip (near Flamingo Blvd) tell the cabbie to take Paradise. That's a $5 dollar savings each way right off the bat.

Even for a day trip elsewhere you can find rental companies that will deliver and pickup from your hotel.

I never rent in LAS but I've been using Alamo/National for other rentals and neither requires a CC for booking.... Never any bogus charges and so far I've been very happy. Always book the cheapest car and more often that not get something a class or two above that.