hike yet, let alone backpacking. Frankly speaking, I do not recommend you to backpack with zero experience. It's just like running a Maranthon for a person who never runs. Seems very simple, by the end of the day, only torture and injury yourself.
For a day hike, however, you only need to bring enough water, 2 or 3 litres at most, and enough snacks. Other stuff, just like 小黑猫 suggests above, pay a visit to REI without considering cost.
And please pay a close attention on how to use them correctly.
