I believe DTV is the only service that offers NFL, not sure about the others.
These days you can get a 2 room system for close to nothing $100, installed for free. They will require a year of service, or something like that.
Prices are about $150 for NFL, $80 for college hoops, $120 NBA.
If you time your purchase correctly, i.e. close to football, you can usually talk them into giving you NFL ticket for free for 1 year. A freind of mine did that last year.