Can I support a friend's new business without buying her $300 course?

My friend sent the launch link and wrote, "I'd love to have you in the first group. It would mean so much."

She's offering a $300 beginner photography course. I've seen the topics listed, and I'm not looking for instruction at that level right now. I can afford the course only by delaying something else I actually want. I don't think the price is necessarily unfair; it just isn't a purchase I'd otherwise make.

She has worked hard on it, and I want to be encouraging. I offered to celebrate the launch over coffee. Her reply was, "Customers are what make a business real." That left me feeling as though friendship was being measured through the checkout.

Would you explain why the course doesn't fit, simply decline the enrolment, or find another way to help? I don't want to promise recommendations I can't honestly make or buy a place just to make this conversation comfortable.