Online Course Sales via WordPress

I'm in need of a WordPress website that will serve as a platform for selling my online courses - aiming to list between 10 to 20 initially. The target audience for the courses is unspecified, therefore, the design should be universal and appeal to various demographic groups.

Key Requirements:
- User-friendly course directory
- Secure payment processing setup
- Course preview features
- SEO optimized for maximum visibility

Ideal Freelancer:
- Extensive experience in WordPress
- Graphic design skills for user-friendly interface
- Understanding of e-commerce rules and regulations
- SEO knowledge.