Yes, you can buy Minecraft with a Visa card
Nope
you can buy a gift card a target and best buy.
uhm yeah sometimes but i have a master debit card and i cant buy it :P
Paypal you can now buy a gift card at target, best buy and other major stores.
Yes. You can buy it with a credit card or via Paypal from the Minecraft website. It is 14.95 euro which comes to $21 US.
Yes, it's absolutely safe. I have done it, and it worked perfectly fine. According to Minecraft's websites, 3.5 million people have downloaded the game so far. If anything wasn't working like it should, someone would have reported it a long time ago.
No, you don't need to anyway. You buy it using Paypal or a card at its website.
No but you need an Paypal or credit card to buy it so ask an adult.
no. some people might be selling them though for money.
You have to download it on the minecraft offical website. It is "minecraft.net". Or just type it on the google and the link will come out. It is safe to buy and download it in the minecraft site. Also you can download it when you have a account and bought it.
No. Why would it be? The download is safe if you download it from Minecraft's home page. The link can be found under "Sources and related links" below this answer.