GoAffPro provides you with the option to allow affiliates to set their coupon codes on signup.
To allow affiliates to set their coupon code on signup, go to the Signup Page section in the Look and Feel tab of the GoAffPro admin panel.
Here, click on Select & Customize.
This will open up the Sleek Signup Page section.
Now, check the "Coupon Code" option.
Finally, click on Save.
After this, the coupon code field will get added to the signup page.