Answer:
I am your most powerful weapon; I come before your eyes. I help you seek the truth, yet I often give you lies. What am I?
I am a mini solar powered computer
Flat as a leaf round as a ring. I have two eyes but can't see a thing.
*forward* *backwards*is what I do all day. I come in all different shapes and sizes. I can be scary and I can calm you down.
I am bought by the yard but worn by the foot
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.