Tin, sulfur and diamond are examples of pure substances which are chemical elements. All elements are pure substances.
Water, sugar, salt and baking soda are pure substances which are chemical compounds. Chemical compounds also are pure substances.
Depending on who you talk to, homogenous mixtures may be considered examples of pure substances. Examples of homogenous mixtures include vegetable oil, honey and air.
Inhomogenous mixtures are not pure substances. Examples of materials which are not pure substances include gravel, your computer and a tree.