Insole becomes handy when you bought a shoe and it is not really fit. I think this will happen when you buy the shoe online. I faced this problem before. My sister bought me a pair of shoe. But it is too big. Although with the insole inserted, it still have some space in front.
There are many kinds of insoles in the market. If you are looking for one, you can find spenco insoles here. They come with different shape, size and style to fit your needs.