Unfortunately, no, not really. All the apps that allow you to watch NFL games (Fox Sports Go, NFL, ESPN, CBS, NBC Sports) all require a cable/satellite subscription to use them. While CBS is a stand alone subscription. But always remember, you can still watch most of the games with an OTA antenna.
As for Sunday Ticket, there are restrictions on who can subscribe to the streaming only package. You must be a student or you must live in a building that does not allow installation of satellite dishes.