If you have viewed the page of a Udemy course which has an absurd 85% limited time discount if you buy within 5 hours… and returned a day later to find the offer has gone and the course is now 95USD:
open it up in an Incognito tab and you should see the discount has magically re-appeared.
Sometimes these offers are only for “new customers” and the discount will disappear again if you log in. If you are willing to create a new account for each course and are using an email service like Gmail which ignores chars after a + sign you can associate an infinite number of Udemy accounts with that one Google account and inbox.
eg. using the gmail account [email protected] I can sign up for two accounts, one with [email protected] and a second with [email protected] whilst receiving all emails in the [email protected] inbox.
Using a password manager like 1password makes it easy to keep track of these accounts, save the course title to the 1password login description.