Foreign Money Exchange is literally the ONLY good currency exchange in Las Vegas. The bank? They'll rip you off. The airport? They'll rip you off then rip your heart with their terrible exchange rates.
If you're coming from Las Vegas BLVD, it'll be in the complex after The Royal Resort. Park in the underground garage. Take the elevator to the first floor, it'll be on your right side. Walk in with your cash money. Validate your parking pass. Walk out with your foreign cash money. Success.
Foreign Money Exchange was able to change me out for over a thousand in Yen with no issues, the exchange rate was about 1% different from market value.