When I had a series of treatments with ozone from my medical doctor, who had a huge, very sophisticated ozone machine in his office, then I could experience, that this indeed was very effective to heal my Fibromyalgia. So I searched for an ozone generator with a reasonable price I could buy, because the treatment was expensive and for the price of three or four treatment series I might be able to  buy my own generator. 
After I had some bad experiences with several cheap generators I bought at EBay and that didn't work at all, I found a generator in the Internet that I could use for all kind of ozone treatments and also for the sauna. I had to buy two of them to get a good price. So I bought these. I was not so happy finding out that one of them was totally broken during the transport. But the other one worked and I could start the treatments with insuflation and ozone sauna. I was excited and felt better day after day. But then to my great disappointment the ozone generator gave up functioning. I wrote to the seller as there was given a guarantee, but it turned out to be useless. The generators were fabricated in an 'underdeveloped country' and obviously so badly, that the vendor closed his business...
I searched intensively and finally found one that seemed that I could trust, because it was sold by a person who obviously was a specialist in ozone treatments with a lot of experience. So I bought this ozone generator. Like  the other generator, it had to be fed with oxygen from a bottle that I could get from a supplier for melding. I had these already and so could start again with my treatments. 
It worked surprisingly good and without any problems for the next years until I was totally healed and I am still using ozone when I do my weekly sauna. 
The last time I am receiving the question from people where to get a good ozone generator and as I know from my bad experience, that there is so much junk around, I will recommend where to get one, with this avoiding similar disappointments I had. 
The generator I am using, you can get from plasmafire.com.  Dr. Saul Pressman, who runs this company, also has created an Internet group:  ozonetherapy@yahoogroups.com 
where one can ask questions and find free advice for every thing about ozone treatments for all kind of diseases and for many that are said about not having a cure... Even though I am totally healed from Fibromyalgia, I am still subscribed to this group and reading there, learning a lot. So I am convinced that Dr. Saul Pressman (even though he is a medical doctor) is not in the first place a salesman, but is doing his best to help people to be healed. So I trust him. 
With this page I am answering the question where to buy an ozone generator and I hope, that this will save you a lot of troubles...