If anyone is interested, you can now get Free By 50 on the Kindle The cost to subscribe is 99¢ per month ( I get a cut).
I understand the Kindle has a basic web browser built in. So I would highly recommend using that to read Free By 50 for free instead of paying. But I don't own a Kindle myself so I can't tell you how best to go about doing that.
If you prefer the subscription service then its now available.