Here’s an email Evernote sent out to users of their free app to get them to upgrade to their premium app. Leading with a 40% discount offer, and the ability to “take evernote anywhere”, which is compelling because you can use the app on unlimited devices as a paying user.
The button copy is also straightforward and compelling. Instead of “SIGN UP FOR PREMIUM” they again focused on “SAVE 40% ON PREMIUM”.
The graphic and overall feel is very on-brand, and they still add value to this email by linking to advice on how to stay productive and how to use their product when traveling.