Ahhaaaa, my perfect question(:
First of all, you especially need a ball. A ball is useful for practices at home, or even if you go to a park and practice.
Next, you'll defiantly need kneepads. When diving on the floor, it hurts without kneepads. You can get them at local hobby/sports stores and sometimes at Target/Wal-Mart. (They may look big at first but their really good protection).
And you'll also need sports shoes. They don't some specifically for volleyball, but you can buy shoes made for running/other sports. The shoes keep you from gliding all over the floor and help you run faster.
Finally here's some miscellaneous items that may come in handy:
-Water (Of course)
-Lotion
-Ponytails (Required unless short hair)
-Uniforms
-Extra pair of volleyball shorts
I hope this helps; I've been playing for three years and I LOVE it (:
Chat with our AI personalities
-Obviously, a volleyball.
-Gym shoes are needed for indoor volleyball, and no shoes are needed for beach volleyball. Socks are a must if you are wearing gym shoes.
-Knee Pads are not required for indoor volleyball, but they really do help a lot.
-Hair up in a ponytail with a headband (If allowed).
-Water
-A Uniform, if needed/required
Hand/eye coordination, instantaneous reactive algebraic equations, stamina, and aerobic exercise are necessary for competing at volleyball.