How much less do the pens that use the cartridge cost?

Where to put the Insulin? Thanks for the information. My husband is on one shot a day of very long lasting (I think that's what it's called) insulin. He takes one shot of Lantus (20 units) and it's suppose to last for 24 hours. I did go to lantus's site and read alot about this product. They have basically said that it can take up to 2 months to totally get this right and that we will see a rise and fall of the glucose (especially because he was only on pills before). It also talked about upping the dose every 3-5 days by a couple units until it was at the target range. Another thing it said was that once he starts meeting his target the chances are that he will have to back down a couple units as it takes time to build up in the blood. It told us better where to give the shots. The doctor handed us a insulin pin, a package of needles and a booklet about it. The only reason we had any ideal where to start is because of this group talking about it. We have started to give it in the arm and it seems to be better for him (less pain). I also learned that it doesn't need to be refridgerated and is probably better if the pen is not. The extra pen inserts do need refridgeration but no the actual pen.

All in all we are very pleased with the improvement of mood. Fewer mood swings. He's not so sleepy all the time and he can think more clearly. Niether of us are stressing so much any more. Which is great. I know I have been stressing about his glucose but that was not as much as it was about him having to start insulin and wondering if I could give him a shot if need be (well he can't reach the spot that doesn't hurt so I do give it to him). So thank you all for your help and support.

I use the disposable pens. How much less do the pens that use the cartridge cost. More specifically, not the reusable pen, but the little vials it uses? Looks like it would be cheaper.