One trader asked me about a course that apparently showed one price, but had a higher price on checkout, why is that?

Normally that never occurs, but if you're using an outdated browser, or have non-standard cache settings, you may be looking at an old version of the site that's stored on your pc's browser cache, prior to a price change.

To show the current version of any site, hit Ctrl-F5. That loads the current version of any site. Normally browsers are set to automatically clear cached old pages; if you changed that or are using an older browser it may inadvertently show outdated/old pages. Or, view the site from a different browser to see current updated pages. Here's info on clearing your cache (just hit Ctrl-F5 should be fine):

I routinely change/update pricing on my sites, so be sure to press Ctrl-F5 to see the current page, if you're using non-standard browser cache settings (or look at it from a different browser). Firefox or chrome are top browsers.