$20 To $60 Bonuses For Existing Discover Credit Card Customers - YMMV

In this SD thread, SD members describe how they have been able to get many of these credit card promotions by calling Discover.

• $1 cash back on each transaction for a month ($20 max)
• $1 cash back on each transaction for 3 months ($60 max)
• $50 for spending $1000 or $2000 over 2 months

This is a Your Miles May Vary promotion that requires some luck and knowledge of Discover's customer service. Refer to the thread for the details.