What is the difference between cheaper and frugal?

While both Words have a similar meaning, frugal typically implies a sense of prudence in the choices being made, and cheap implies stingy. Someone who is frugal will evaluate the cost of an item, and consider other factors such as gas mileage to go get the item, and their time required, whereas a cheap person would drive out of their way to save a few pennies, not considering how much time or gas may have been wasted.