The Armed Forces Network does get the feeds for NASCAR and other prime time sports free. Commercials are cut and local area informational spots are injected where you would see the regular commercials.
It has benefits and draw backs. Tonight, Saturday 26 Aug, the Bristol Race is live starting at 0130 in the morning with no Sunday replay. I do get the Truck and Busch race replay on Sunday at a better time.
We also get the Superbowl minus the commercials. Some years when the game is boring, the commercials would make watching it worthwhile. Usually, the day after the world series and superbowl are days off or late reporting to work due to the events being in the wee hours.
I'm not really complaining, AFN has improved every time I have gotten a new assignment to a new overseas location. The first time I was overseas I just has one channel, now we have 8. If you live off base you can easily get a SAT Dish system.