Heads up, Discover cardholders! Keep an eye on your email because Discover is sending out targeted offers for a free $20. The email subject line is "Congrats, [Your Name] — you have a special $20 cash back offer." If you see it, all you have to do is add your Discover card to a mobile wallet like Apple Pay, Google Pay, or Samsung Pay and spend $100 by the end of the year (December 31, 2024). This is basically free money! Most of us are already using mobile wallets for everyday purchases, so hitting that $100 spending requirement should be a breeze. It's a quick and easy way to pad your travel fund or treat yourself to something nice. The offer has reappeared as of January 8, 2026, so check those emails! There's no stated end date this time, but don't wait too long in case it disappears again.