Limit on discount code

Hello!

I would love to see an additional feature for the discount codes - a way to create a ceiling on the limit. 

For example, I would like to offer 10% off my nightly rate UP TO $500. 

Current OR only offers a percentage or dollar amount off, not both. 

Thanks!

A limit on how many times that discount code works would be great as well. I would love to set up a single use code to send to people and run promotions with. 

Also, it would be nice to restrict a discount code to be used only once. Not sure if that is possible now.