Here are the terms and conditions from their website:

*20% off Sitewide Coupon: 20% discount up to $40 maximum discount valid from 12/11/17 at 12:00AM (PST) until 12/11/17 at 11:59PM (PST) or until promotional funding is exhausted, whichever occurs first. Rakuten.com reserves the right to cancel, modify or limit the promotion at any time in its sole discretion. This promotion is open only to individuals 18 or older and must establish a Rakuten.com account or be signed into their Rakuten.com account to apply the Coupon Code GREEN20. This Coupon Code is valid for one-time use when the total value amounts to $40 or more. This Coupon can be used only once per account within a single transaction with one merchant, while supplies last. Limit one redemption for each coupon per household. Coupon code exclude certain products due to the merchant’s sales restriction. Gift cards cannot be redeemed in conjunction with this promotion. Bulk purchases made by re-sellers do not qualify. This promotion is not valid with any other offer. You are responsible to pay for any applicable sales tax on your purchase and this is valid in U.S. only.

Adorama sells through Rakuten so this is a way to get a killer price on some various things like the DA 50, the DA 35 and the 55-300 PLM.

Get the 55-300 PLM for $332.

Sorry about posting this so late but I was busy today.