I have two PC 2700 333 DDR 512 MB ram chips.
One is Kingston and is used; I used it with my powerbook for a year and half with no kernel panics (at least from ram - stupid MS Excel)
The other is Apple Ram, never been used, and will be supported in case you need to send your Powerbook in for repair. I bought a new 12 inch - ordered it with the 512 MB chip and decided now, I would prefer a 1GB chip - so that is why it is new.
I accept Paypal and would be fine with putting in on eBay with a Buy-It-Now for either chip.
used chip - $59
Apple chip - $69