Disclaimer: This post does not apply to people in Sacramento or in the Kings home territory.
It depends. I get CSNW for free, presumably because I am close enough to Northern California that it is one of the two or three regional sports networks they give you for free. I don't know if you get it. Check channel 656. If it works, then you don't have to pay extra to get the channel itself. If it doesn't, you'll have to get the sports pack, which is a premium service like HBO, Starz, Showtime, etc. The prices for premium services on DirecTV are $12/month for the first one, then $11 for the second, then $10, $8, and $7 dollars. You can also get the Premier package that gets all that stuff if you already have all the movie channels. That means it will be about $72 for the season if you don't hve any other movie channels. Along with the CSNW, you get a bunch of other regional sports networks, as well as NBA TV (I believe).
Now, that tells you how much it would cost to get CSNW. As far as how many games you'll see, my best guess is 0. Yes, zero, zip, zilch, nada. I think it was a glitch that allowed some of us to see games last year. Those games should all be blacked out if you live in Warriors, Clippers or Lakers territory, or any territory outside of the Kings. It was a new channel so I think they messed up and let some through. I doubt it will happen again, and I certainly wouldn't count on it.
At best, if you pay for the Sports Package premium service, you might get to see some of the games replayed the next day, as well as the 9 games on NBATV that you wouldn't have been able to see otherwise. That's not enough games to be worth it for me, so I've got to stick to the 11 nationally televised games and hope that they forget to blackout CSNW often this year.