The decision to use oxygen or not is up to the particular climber. Some think that by not using oxygen, they think that they are tougher or more prestigious. Most climbers though, decide to use oxygen. They usually start to use oxygen at Camp 3. The main provider is a Russian company called Poisk.
This company, founded in 1929, produces oxygen equipment and metal-plastic vessels. The piece of equipment that the climbers use contains four parts: a stopping valve, a light oxygen-bottle, a reducer with a gas flow regulator and a bayonet join. Each cylinder is tested
The price for each depends on whether you purchase a 3 Lt or 4 Lt cylinder. If you choose the 3 Lt cylinder, the prices for each will be: $385 for 1-20, $372 for 21-60, $360 for 61-100 and $350 for 101-200. On the other hand, if you choose the 4 Lt, the price per cylinder will be: $410 for 1-20, $396 for 21-60, $385 for 61-100 and $372 for 101-200. As you can see, the price decreases as more cylinders are purchased.
Seeing as two bottles last about twelve hours, one is advised to bring five bottles to be safe. The most common problem encountered when dealing with oxygen is having it run out. If you are close to the end of your expedition, this may not prove harmful. If you are towards the top of the peak and you run out, it could make for an extremely dangerous situation. This problem occurs more than expected. Climbers sometimes think that they are able to go father distances with less oxygen.
All in all, a climber should be very cautious with their oxygen. They don't want any to leak, get stolen or be misplaced. There is enough inevitable danger on the mountain that they don't need problems with their oxygen.