These 3D Minecraft models are only some from a massive batch, with each being made with the help of a new program called Mineways.
Mineways is free and makes it very easy to extract a model from a Minecraft world map. It then performs rendering operations after which the result is sent to a 3D printer. In this case, the images shown are from Shapeways, a 3D printing shop that already has over 1900 Minecraft tagged items on its site and Flicker group that are either for sale or download.
Mineways has made head progress with new updates from developer Eric Haines. The latest version runs on both Windows and Linux and allows you to output Minecraft models in full color. It has helped bring access to thousands of interested people and its popularity will only grow in the time to come.
Haines has also provided the code of the program as open source on the Mineways website. Additionally you can head there to go through a comprehensive tutorial page set to help newcomers.
As for the prices of 3D prints, these can range from $5 to $500, depending on size.