Where to buy a Combo Drive for G3 iBook?

[Soire]

Hey I was wondering if it was worth it to buy a combo drive to replace the old "CD-ROM" (sounds weird just saying that) that came standard on my g3 500Mhz White iBook.

Any links or suggestions? The cheapest apple branded part I could find was $250 which is pretty damn expensive. Then there's the Toshiba one for around $150, but I don't know what's compatible...

thanks. :)