Always Get a Raincheck!
Some stores will give you a raincheck if the product is out of stock.
For example the Arm & Hammer laundry soap was on sale for $2 at Loblaws banner stores but at that price, they ran out quickly.
Also, they only had limited stock of the type that the $1.50 coupon worked on, and that sold out fast, But with the coupon, the A&H was only $.50 a jug.
A raincheck is usually good for a month so you have plenty of time to go back and get the product after the sale is over.
It’s the best way to get a supply of a certain product to stock up on for a very cheap price.