Buy Siege for $36, and you then get $36 to spend in their store.
Direct quote from the page:
"*If you purchase Rainbow Six Siege “Standard”, “Year 2 Gold edition” or “Complete Edition”, you will receive A$35.99 in store credit. In case of a promo code usage, the store credit amount will reflect the amount paid by the user. Store credit will be in the form of a promo code that will be sent via email on September 7th. The store credit can be used on any item sold on Ubisoft Store during a 7 days period from the date of receipt of the email. It is a one-time use only code and no balance of unspent credit can be used on future purchases."
So they dont send you the code until all the current sales are over and then give you 7 days to pick one of their overpriced games to buy which in the end will be more expensive then if you just bought it during the current sale?