Codes are listed and updated in the Deals, Freebies and Resources "Kobo" thread. It's very active! Members receive codes by email and share the info on this thread. Some can be used only once, but in some cases changing the suffix ie: using au instead of ca etc. will allow you to get multiple discounts with the "same" coupon code. It's pretty well explained in the thread. Discounts of 30-35% are pretty frequent.
***There's some really good discounts today for Cyber Monday. See this post by Apesmom for details:
https://www.mobileread.com/forums/sho...72&postcount=1