To redeem the 20% off, enter the coupon code RFD20PUMA against regular-priced items purchased by April 4. Or, if you prefer, you can have your order ship for free if placed by April 1. Free shipping applies to both regular or sale-priced items, but cannot be combined with the 20% off. Standard shipping charges are $9.95 per order, so the free shipping pays off the most if you're spending less than $50 (or purchasing sale items).
Keep in mind, that as Shop.PUMA.ca ships from the US, additional taxes and duties may be applied to your order. For some shopping tips and reader-faves, check out the RedFlagDeals.com forum thread on PUMA's free shipping offer.