From your article, I quote:
"The price for snapshots will be $0.02 per GB of snapshot storage per month."
Let's say my droplet has 40GB capacity and my total disk usage is 10GB, what constitutes the snapshot size? 40GB or 10GB?
You will be charged only for the used space and not the entire disk image. We are not currently charging for snapshots. We just mention the price in order for people to not be surprised when that day comes. Before then, we will make it much more clear and display the usage size of the snapshot.
I'm also glad that it's free. And I think that if you ever really charge for snapshots, that you should just charge starting at a certain size or number of snapshots.