Strange Noises while Driving my RAV4

[amodini]

I have a 97 RAV4L (4-Door) with 100k miles on it. Since few months, I have strange noises coming while driving.
1. There is a 'Cling' noise that comes up once in a while especially when I am driving up or down hill. This is loud and goes away on its own. This doesn't happen all the time so I cannot replicate it when I take it to the mechanic.
2. There is a 'Wu-Wu-Wu........' kind of noise comes all the time when I drive. The faster I go the more noise it makes. I took it to the mechanic several times and they said everything is fine. One mechanic showed me that my tires are worn out more on the inside than outside. He said that's causing the noise and this is a know issue for RAV4. The wheels are balanced, tire pressure is fine but don't know the reason for this uneven wear and tear.
I am afraid to go the dealer as they might say something and give me a big bill to fix it and I am not sure if they would be able to fix it.

Can someone please get back to with a solution to the above problems. Its really annoying to drive with that noise.

Thanks,
AModini