What is an inertial frame of reference? does a perfect inertial frame of reference exist, and if it does, give me an example?

Within the realm of Newtonian mechanics, an internal frame of reference or internal reference frame, is one in which newton's law of motions is valid

This phenomenon is known as parallax. The simplest example is this: if you are sitting in the passenger seat, the gas tank needle may appear to read empty. However, if you are the driver, you will see that you are not on empty, but should get some gas.