https://www.flydenver.com/

The currency of the United States is the US Dollar. 
The currency code is USD and the symbol $.

Convert currency at your bank, or at the airport before leaving or upon arrival.

Check current exchange rates at Xe Currency Exchange currency converter.

ATMs are widely available to withdraw cash. Please note exchange rates may be higher when using ATMs. 

Credit cards are widely accepted. 

*For ease of payment, please let your credit card companies know where and when you will be traveling.

If you require a visa invitation, email Customer Service

They will require the following information:

Passport name
Passport number
Address
Phone number
Class dates
Approximate travel dates

• If you arrive within the first hour after class starts you will be charged an additional 20% of your class fee.
  
  
• If you arrive more than 1 hour after class starts you will not be allowed to join the class.
  
  
• If you leave before the facilitator ends class, for any reason including travel arrangements, you will be charged an additional 20% of your class fee.

https://www.denver.org/places-to-stay/by-area/downtown/