What? You don't have a credit or debit card? Or at least parent permission to use their card for just $5?
"But David, you already have Blockland. Why would you buy another copy". Or, "No."
No I don't have a credit card, I'm 14. As for debit, I bet my parents wouldn't trust me with one, even though I never lost any card I ever had. Even the fake credit cards they give out as advertisements that I kept in my large wallet when I was little.