That's awesome - I would be one of the people who would pay $400 to be carbon neutral each year. You should think big and do a Kickstarter with $25 gifts up to $5k gifts...
For $400 I want a t-shirt that says "I'm carbon neutral. Do you have the rocks to become carbon neutral too?" with a pic of olivine rocks and your website url.
For $400 I want a t-shirt that says "I'm carbon neutral. Do you have the rocks to become carbon neutral too?" with a pic of olivine rocks and your website url.