How do I set a standard price for the room rental? and how do i set up promo codes?

i don't see a form element to establish a standard room price. i also want to allow for promo codes for discounts. i don't see a form element for this.

Discount codes are available for "Sell products" payment type. So, you can set up your products inside the payment field: https://www.jotform.com/help/165-Setting-Up-Your-First-Order-Form

And then create the coupon code to apply discounts: https://www.jotform.com/help/233-How-to-Add-Coupon-Code-to-Payment-Forms

So, you may clone your existing form, and try to set it up that way in the cloned version.

Let us know if you need more help.