The Blue Cash Preferred Card from American Express offers higher cash-back rewards — as high as 6% — but it has an annual fee: $0 intro annual fee for the first year, then $95. A good guideline: If you spend more than $61 a week at U.S. supermarkets, you’ll come out ahead with the Blue Cash Preferred Card from American Express, even after paying the annual fee. For a more detailed breakdown, use the calculator in our comparison article.