The week card is kind of a stamp card. Every Monday morning you start fresh with no stamps. If you do x purchases you reach the best possible price level and this is your personal deal throughout the rest of the week.

For example: motivate your app users to purchase a lunch offer of a baguette and a fresh juice. At first purchase the discount is 10%, on the next purhase the discount is 20%. Then from purchase 3 and onwards (as many purchases you like) within the same week you get a discount of 30%.

The week card can be presented for the app users like a stamp card where you climb to a better price and get stamps, but it can also have a design which communicates the next price and how to lock in the ultimate price level.