Sweet Earth May 2020 “National Hamburger Day” coupon campaign will run from May 28, 2020 (3:00am PST) – May 29, 2020 (11:59pm PST) or while supplies last. To request a coupon, you must be 18 years or older & USA resident. Coupons for free product (up to a value of $5.99) are only available while supplies last OR only for the first 10,000 respondents. Campaign is limited to one (1) coupon per person/email address/household. Coupons will be mailed out via US Mail within ten (10) business days of the campaign end date May 29, 2020.