Ahh, the secret is out! Yep, this went out in a release over the weekend. We haven't written docs yet, but it's pretty simple:
1) Go to Settings > Surcharges & Discounts and add one
2) Select the Discount type
3) Select Applied by Discount Code and enter the code
Once you have discount codes that apply to a property, the discount code box will appear on the guest form for a quote as well as on the book now widget. The discount code box won't show if there are no applicable discounts.
The other thing to keep in mind is that a discount code will override any other discount on the quote. So if you have a last minute discount or something, and the guest enters a discount by code, it would replace the other discount instead of stacking with it.
