Adding a Coupon to Appointments+

I see that I can have a discount for appointments based on membership level but I don't see a way to apply a discount code for a regular appointment.
Use case: I have a webinar and activate a limited time coupon to book a consult at a reduced price.
I've been reading the threads but couldn't find any there were current, is Marketpress still the only way to do this? If so, how? Thank you!