Hi Helen,
Yes you can do this through Smoothbook. Select ‘settings’ -> ‘charging’ from the main menu, you will need to connect your Stripe account before you continue.
Scroll down to the ‘packages’ section. Basically you’re going to add a package for your service / class with the discounted price. Once you’ve created the package with any options that you like click ‘save’ to return to the charging page. You will see a column in your list of packages: coupons, you want to click on the ‘manage coupons’ link for the package. There you can one or as many coupon codes as you like and then send these to whoever you like.
Keep in mind that if you create a payment option for a service then your users will have to choose at least one option: your service will only be available to people with the code. If you would like others to be able to buy the service for different prices or with / without a coupon you will need to add other payment options (you can create a package with zero cost if you’d like an option where people don’t need to pay.
Hope that helps!