Normally, to maintain simplicity and consistency with option characteristics, we discuss shares in bundles of 100. Shares, however, can be purchased in any amount you choose – even if it's only 1. Below you'll find the risk profiles for differing amounts of shares so you can compare the risk and reward to the standard 100-lot (shown as a gray line).
Notice the dramatic change in P/L rates as the number of shares increases. It goes from a walking speed at 10 shares to a Lambo at 200. Smaller accounts will be more likely to trade in less than 100 shares, or avoid them altogether. As a person with a small account, I almost never trade shares because they tend to be too capital intensive.