Go to your browser and watch. It's best for the west coast games because they'll start at about 10 our time.
$39.95 for 50-ish games is a good deal. It's a little more than a dollar each.
It's preseason football. Are you really going to watch the 3rd preseason game between the Raiders and Panthers?
And like Linty said, you can watch them for free at some point or another. But hey, if you think it's worth it, more power to ya.
