How it works
In the made-up village of Maple Bay, Mo's rewards card gave one coin back for every full twenty coins spent. That is cash back, a small discount on coins already being spent.
The card had a yearly fee of two coins, a price for having it, used or not. Spending forty brings two back, and the fee takes them.
A zero-extra deal adds no coins as long as the deal is followed. Every deal has an end date, and a coin left on the last day brings extra.
An offer is worth what is left after the fee and the end date, so read the small print first.