At the bottom right of the main page there is a "sign up for email and save $25".
I received unique code within a couple minutes. I believe codes are valid for 14 days.
This Coupon can be used on only one item and can only be used once by its recipient and is valid for $25 off your purchase of $50 or more from HSN.COM. Coupon number is non-transferable. Coupons must be applied when order is placed. Excludes shipping & handling, sales tax, This Day Only offers, and clearance items and can only be applied to the first shipment of Auto-Ship items. The use of this coupon may disqualify the order from inclusion in other promotional offers or discounts. Coupons cannot be applied to or combined with other coupons. Coupon is not valid for Arrow Sewing, charitable contributions, gift cards, Janome, Samsung large appliances, selected footwear, the iRobot Roomba 880. HSN reserves the right to cancel or change the offer at any time. We reserve the right to cancel orders when unexpected coupon system errors occur or in the case of abuse, misuse or fraud in connection with the coupon number. Offer is valid 09/02/2017 - 09/16/2017. Coupon Expires on 09/16/2017 at 11:59 PM ET.