User blog comment:Agent Spy/BOARDSCRAFT 1.7.5 NEWS BLOG/@comment-5112967-20140402010451/@comment-4052371-20140403004250

By default, the resolution is 16x16 pixels per block. You can get texture packs that have higher resolutions, but it may drain your computer's resources, due to the fact that (depending on your render distance) Minecraft has to load hundreds of thousands or millions of blocks into memory (of course, it doesn't render them all at the same time).

Also, I don't think you can use an Amazon card to get it. If I remember correctly, you have to buy a physical Minecraft card in a store like Target or Gamestop, or pay for it with a credit card online.