Not sure if this is considered a “hack”, but I’ve been doing this lately.
Start Cole’s plus offer mid month, get the 10% offer to use straight away and also get the 10% offer next month when the next month starts. Then cancel as soon as you use the 10% offer next month. Getting 2 x 10% for $7.
By doing this you effectively get the best part of Cole’s plus saver 2 months for the price of 1.
Rinse and repeat on 3rd month.
Does the discount activate immediately so you can sign up just before checking out?