Here's an email I received from a reader who earned a good amount last year using her Blue Cash from American Express card:
I read on your site a lot about using Amex Blue Cash for the cash back rebate. I just want to report that after a year of charging almost everything on the card (and paying it off each month), my husband and I earned about $566! Our return on our total charge amount was around 3.7%, enough to purchase a new laptop for my husband, which he really needed. We're really happy with the program and look forward to our rebate next year.
Ok, that 3.7% seems really high. I tried it mathematically and the only way to earn that kind of return is if they spent everything on gas, groceries, and drugstores (these earn 1.5% initially and 5% after the first $6,500 in charges) and $16,000 in total. This gets $568 in cash back and 3.57% return. Close enough to what she said happened to prove it's do-able. Then again, maybe she got some sort of bonus sign-up incentive that made the card even more lucrative. In that case, 3.7% is certainly achievable.
Just goes to show you -- if you match the right card with how you spend your money, you can really maximize your cash back.