I love to add ginger to my entrees, but found that even the smallest piece would go bad before I used it up. Then I discovered that you can freeze the ginger without peeling it, and then grate it into your recipe as you need it. Now I buy the biggest piece I can find, and always have it on hand when I need it.
Just put it in a plastic bag or container, unpeeled, and grate it frozen into your food. I use a rasp to get it finely chopped, but a regular cheese grater works just as well.