Allow User to Sign Up for Only One Course

Hello,

you can achieve this using WooCommerce. Here’s how the system works, first you need to create a product with WooCommerce, set the price (regular or sale), and then publish it. Once an item is created, you can then link that product to a course and the course will be sold via that product.
for more information, please direct to this link: https://docs.themeum.com/tutor-lms/ecommerce/woocommerce/

Thank You