In My Side of the Mountain, the type of suit that Sam makes for himself is a deerskin suit, designed to help keep him warm. He makes the suit in chapter 11. In this chapter, he realizes that he has grown out of his old clothes and that he will need warmer clothes to survive, anyway; in the previous chapter, Sam found and stole another hunter's dead deer and used its hide to make a weather-resistant door to his makeshift home. Seeing the insulating qualities of his new door, Sam realizes that making clothing of the same type would be a good idea, so he sets out to trap and kill his own deer for this purpose. After some difficulties, Sam succeeds in this, and with the industriousness that again and again saves his life throughout the book, he proceeds to make himself an entire outfit made from warm, lightweight deerskin.
This industriousness and thoughtful use of natural resources to survive is typical of Sam; even in this one instance of the deer, he endeavors to use every possible part of the animal, eating the meat, using the bones for tools, and tanning the hide for shelter and clothing. In today's throwaway society, we can learn much from Sam's careful use of natural resources.