Home Depot 15% In-Store Coupon

I'm currently moving and would soon like to make a big purchase in Home Depot. Lately I have seen a few people that made an in store purchase with a 15% In-Store Coupon, and would like to get the coupon before I make the purchase. I asked them and they told me that they were just sent to their Email. I just wanted to know how do I get that coupon (and I have been told other coupons too) via Email. Do I need to subscribe to something in order to receive them? Who receives them and what do I need to do to receive them by Email? Thank you so much!