On some big events such as Black Friday, Valentine's Day,... edX will constantly offer up to 50% discount or more, so all customers can purchase well on their budget without worry.

In case you enter a discount code during checkout that doesn't exist or isn't currently active, then you can see the message: “Unable to find a valid discount matching the code entered”.

Normally, edX will make it easy to use online coupons with scannable barcodes, such as 52% off your entire purchase, in-store. ... You can check your edX digital coupons to use In-Store.

Yes. Coupons for each Discount Event of edX will be collected here while being updated day by day. Sometimes, there will be deals not updated promptly but it's rare, we expect sympathy from you. 

All deals from Promotion Programs of edX are collected here. For each certain occasion, its coupons will be on the top of the coupon list, and surely they always come with an expiry date.

Yes. Like all other stores, edX offers a number of Cyber Monday Coupons. Don't forget to check the expiry date before making your purchase.