Can work out to be more expensive due to time it takes instructor to goo over presentations.I'm gonna chime in here. I took the PADI Nitrox online course. As soon as I was done, I felt like I had been completely ripped off. I paid essentially double what it would have cost to have taken it in person. Sure I learned all the important aspects of Nitrox, and felt absolutely well enough informed. It just cost way way too much. I would highly recommend finding a local dive shop, and have them give you the course.