It was revealed that Super Mario Run will become available on December 15th. It's going to come at a price, as well.
As far as I am can see, as of the time of writing, it looks like it'll be around £8 for us over here in the UK. I haven't got this confirmed from a proper source, though. Therefore, I would not be surprised if it ends up being higher than that.
I'll buy it. It sure will be unique to see Nintendo's most iconic character on a platform other than Nintendo.