What kind of noise is it? The Prius is front wheel drive, is it a clicking sound that increases with the velocity of a tight right hand turn? If so it could be a worn CV joint which would require replacing the axle. turn the wheel fully to the right and look in from the front bumber. At the back of the wheel you will see a shaft with a rubber boot. The rubber boot keeps grease in the CV joint is if the boot is damage grease will be flung around the inside of the wheel and steering knuckle. There is also a possibility that the front sway bar link has broken, it is too hard to guess without hearing the noise first hand.
Have you had your car tyres changed recently.
I once had my tyres changed and almost immediately after it started making this awful noise everytime i turn. I went back to the tyre place and they insisted it was not the cause.
I had the belt changed, oil change, all sorts of repairs with no luck.
One day i had a flat tyre and called the AA to help. They then found out that when u had my tyre changed they had put an incorrect rim and insisted that i change it.
The minute this was changed, the noise stopped.