No, you don't need to pay for it again. All you need to do is remember your Bl Key.
Nobody remembers their Blockland key, just send a new copy to your E-mail though.
i do. i know it off the top of my head.
Just delete blockland.Then go download it again.After you do that go to Key Recovery Put in your email.Go to your email.Get your key.Enter it on blockland.????.Profit
but then if you only had demo you could use his... and that's stealing... and bad. Don't tell people your code