Display prices of $0 as a -

[jonbiemond]

          @jonbiemond In my view, we can confidently assume that a course will always come with a specific cost. The previous issue arose when the site's structure was altered, causing it to consistently display a price of $0.

To enhance the user experience on our frontend, given that we anticipate having to pay a certain amount, excluding $0, I propose representing a $0 price with a hyphen ("-"). This change will make it less misleading for users, as they might otherwise think the course is free. Additionally, if you encounter a "-" in the price field on the table, it's a clear indicator that there might be script issues or alterations to the webpage's structure.

Originally posted by @VleraBllacaa in #59 (comment)