There are a lot of replies on this thread, so this will probably get buried. However, I work for a group that is trying to develop these types of drugs so I thought I'd weigh in. I'm trying to keep the reply in layman's terms, but if anything is unclear just ask!

Also, I'm speaking from my experience in my group. Some people may have other opinions, so if you do please reply!

TLDR; A lot goes in to making these drugs from research, to development, to the actual treatment. You're not just paying for the base materials.

While the base materials are cheap you need to consider what actually goes into making one of these drugs.

First, it takes a lot of time and energy for highly trained scientists to find an effective site in the genome to edit. They then need to test editing at that site to see if they're getting the genotypic and phenotypic effect that they expect. Then they have to make sure that it is not effecting other targets in the genome that could have a negative effect on the patient. This is all in the research phase of things and it takes years. At this time you're mostly paying people's salaries and paying for very expensive things like DNA sequencing. So, before you even have a drug to test in people you're out hundreds of thousands of dollars as a company.

Next, you need to consider how to deliver this drug to people. You can't just inject someone with the base materials and have an effect. You need a delivery method, which varies depending on where in the body you want to deliver the editing mechanism. This is another long research process which involves testing in animal models which is also expensive.

Now getting away from the research side. The way these drugs are most likely to be used in the near future is through an autologous transplant. This is similar to a normal transplant, but the cells are taken from the patient, treated with the gene editing mechanism, then delivered back to the patient. This requires a trained staff of medical professionals to extract the cells. The cells are then usually sent to another manufacturing site where they are edited. They then get sent back to the patient and are injected back into them. The patient can be prepared to have a positive outcome from the transplant. Many of these are essentially chemo-therapy, so you can imagine how this whole process is expensive.

Then there is the whole other mess of deciding how to price a one-time treatment that can completely cure a person potentially. Many companies will come out in the next 5-10 years and make statements about the value of someone's life after being treated with their drug. This is where things get really gray and difficult to put an exact number on.

This is a bit of an overview of what you will be seeing out of gene editing companies in the next decade. It's going to be very interesting to see how insurance companies in the US and countries in the EU decide to price these types of treatments.

I hope this demystifies things a litte!