Lenses for Canon Powershot G3?

[ogre]

Hello, I have a Canon Powershot G3. I have been wanting to buy a telephoto lens, wide-angle lens and lens filters for my camera. I've seen the lenses available on the canon website which are $$$. I've also seen lots of lenses on ebay by various manufacturers which are much cheaper

Is there a big difference between the canon lenses and the generic lenses?

thanks.

~mark

[griffenjam]

I'm assuming one of the generics you have seen is by Digital Optics, I would like to know about their lenses as I am thinking about buying one myself, but can't find a review. I have a PowerShot A70 and I have seen a wide angle lens and a 2.5x telephoto for around $80. That's pretty cheap, but it's expensive if you're buying garbage.