Option 1: make it free, up to a certain dataset size. You can harvest interested leads like the gentleman above.
Option 2: (if you don't want to deal with a huge volume) offer it for $50 one-time fee, up to X size, for Y months (e.g. $50, up to 1 GB, valid for 3 months). Nice way to filter qualified leads.
There are variations from the two options above, but I think you can easily get the general idea.
Thoughts?
