Radon price: $4/m ?? I'm doing some research on Radon. I have to put together a PowerPoint presentation that describes its origins, properties, characteristics, etc. (Each student was assigned a different element.) One piece of information I'm required to report on is current price to purchase a sample of the element. I have found only one source that mentions a purchase price for Radon, and it says "Radon can be purchased for approximately $4/m." - without further explanation. What is "m"?? I assume it must be a unit of volume or mass, but if so I'm not familiar with it. Any ideas?