Sign up for the American Express Cash Magnet Card and you could get a $300 bonus. Get $150 after spending $1000 in the first six months then get 10% cashback on grocery purchases up to $150 in the first six months for a total of $300.
The card has no annual fee and earns 1.5% cashback on all purchases. Not everyone will see the offer or may see a lesser sign up bonus. Try opening the link in private or incognito mode on your browser.