yup, that's where I buy mine. hard to believe how much my LBS charges after getting them from redrock.

+1 for the 12g from the 'Marts. I also carry a mini-pump and inflate a little before I blast it with the CO2. That makes up for the smaller cart size.

Red Rock prices look good. They're inline with the 'Marts for the 12g carts.

I agree the most cost-effective is the Wal-Mart cartridges.

Sure, they are only 12g and are unthreaded.

But they are dirt cheap.

I guess if you are using a mini pump and CO2, a 12g is fine., But, I no longer carry a pump so a 26g threaded cartridge is what I carry.

Since I average about one flat per year, the price difference between a 12g cartridge at 80 cents and a 16g threaded cartridge for $1.30 to $1.50 isn't a big deal to me. If I needed to use two 12g cartridges, the price would be about the same as a 16g cartridge and I would need carry more of them.

I usually carry a couple. So far, I have not gotten a flat on the road (i got one while living my house so i just used the floor pump) but i have "lent" cartridges to individuals in need of assistance on the side of the road.