Making your own sauerkraut is easy, a lot easier than what some here are making out. I have use everything from a crock, the old fashioned tried and true method, to a (food safe) plastic bucket. If you are going to make kraut in a plastic bucket, Please, please make sure you use a food safe bucket.
To make sauerkraut, use the freshest cabbage you can find. The absolute best would be cabbage you just picked, bought from a farmers market, or just got in from a purveyor. You just don't want to use old dry cabbage. Anyway, use the freshest cabbage you can, cut the head in half, remove the core and loose outer leaves. Shred the cabbage into thin strips using a knife or a mandolin. Layer the cabbage into the bucket or crock and sprinkle with salt (the ratio is 5 lbs of cabbage to 3 tablespoons kosher or canning/pickling salt) then pound the shredded cabbage with a wooden spoon or a wooden tamper. The pounding is a very important step, it helps the salt to draw the needed moisture out of the cabbage to make the brine to ferment the cabbage. Continue to layer cabbage then salt and pound, cabbage, salt, pound until all the cabbage is used up. Now place a plate on top of the cabbage to weigh down the cabbage and force it below the brine. I use a bag of salt water on top of this to help weigh the plate down, and have even forgone the plate and just used the bag of salt water, the ratio for the salt water is 1 Tablespoon salt to one cup of water. Too much salt will slow down the fermenting process as will too cool of a place to ferment the kraut. I use this brine/salt water in the bag because if the bag ruptures, it is the proper mix for the brine in the sauerkraut any way, as a matter of fact, if the liquid doesn't rise above the plate, this brine can be use. Don't put a lid on the bucket that seals it if off from the surrounding air, it needs the wild microbes from the air. Instead use a very loose fitting lid or boil a rag in water, cool it and place it over the top of your crock/bucket.
Let this mixture sit in a warm place for 2-3 weeks checking daily. It will begin to have bubbles rise in the mixture, this is what is wanted, it is the fermentation process at work. If a white scum forms, skim this off, wash the plate and replace the cloth with a newly boiled one. If there is no scum, leave it alone. When the bubbles stop rising, the sauerkraut is done and ready to eat. At this point I would move it to the walk-in and keep it at the proper cold temperature for long term storage. I was making a new batch every week at the last restaurant I worked at in Colorado, and we were only using it for Brats and hot dogs so it was moving quite well (they were done in two gallon buckets per batch, filled to within two inches of the top).
Many health conscious people seek out sauerkraut juice to drink because of the helpful bacteria that the mixture contains, so there is absolutely no need to rinse the sauerkraut before you use it. It can be used raw, you can heat it up before putting it on a sandwich, or you can add other flavors and cook it at this point. I had many coming to eat the brats/dogs just because it was homemade sauerkraut. It just tastes better. Some commercially made sauerkraut these days are made with vinegar to get around the fermentation process, this is NOT real sauerkraut, and it will tell you in the ingredient area of the label.
I always tried to do as much as I could from scratch because I take great pride in the product I put out. It adds to the work load, but if I was in this for the money, I wouldn't be in it at all.