What are your dates? If that's the roundtrip price, I'd say that's pretty good. Honestly, the convenience and comfort of JetBlue is worth every penny, so even if you can save a tiny bit of money with somebody else, I'd still pick them.
JetBlue airplanes are fitted with wide, leather seats, and on the back of each seat is a personal entertainment system (a television) that has multiple channels of tv, as well as movies, music, etc. By far the most comfortable airline. JetBlue is FAR better than American (who does not have any of those luxuries), and since JetBlue is already cheaper, I would 100% choose them.
I don't know much about promotional codes, so I couldn't answer that question.