This article provides a few step tutorial on how to provide your first time buyers a discount code in return for their newsletter subscription.
Connect MailChimp
First you’ll need to make sure MailChimp for WordPress plugin (MC4WP) is installed and active. If it’s not, access Rey theme > Plugins Manager and install it there.
Next you will need to setup a new MailChimp account and create an API key to add in the plugin’s settings to connect with it. Get your API key here.

Create coupon code
The easiest way of providing the X amount of discount is to create a WooCommerce coupon code. Access WooCommerce > Coupons and create a new one. Give it a name like “NEWSLETTER10” (it doesn’t really matter, it’s just to have an easy name).
Customize the coupon details as you want, but for the sake of this article, select Percentage discount and 10 as the amount.
Make sure in the Usage limits, to select 1 as Usage limit per user, basically to restrict it for the first purchase only.
Create the automatic welcome email in MailChimp
Back in the Mailchimp.com admin panel make sure to follow the exact steps described in this article https://mailchimp.com/help/create-an-automated-welcome-email/#Create_a_one-click_welcome_automation , and after you’re done, make sure to add the coupon code inside it and highlighted so that the user notices it.
After doing this, the user should receive this coupon code in their mailbox after they subscribed to the newsletter.