Even though he's a butt goblin, i agree with muddytazz...
I have a powertank c02 setup, and when i go for long wheeling trips like blazerfest for a week.. i bring both 10lb bottles, just in case i break down and have to use air tools or fill up a bunch of tires, i have the second bottle filled up back at camp..
I pay about $22 every time i go to get the 2 10lb bottles filled with co2.. and i've already filled them up at least 10 times.. So looking back now, yah pretty soon here i'm gonna get a york compressor and get an on board air setup going so i don't have to worry about my tanks being filled.. one less thing to worry about when getting ready for a trip.