Not tipping the waitress was a good example of his miserly nature. Sue thought her mother was miserly in the amount of pocket money she got, but failed to realise the hardship the family was under.
Use it's (with the apostrophe) only when you mean "it is" or "it has." For example: It's time to go. (It is time to go.)It's been a long time. (It has been a long time.) Use its (without the...