The difference in price is pretty mad and not worth it, and I'd expect the chip to be too fast for your laptop since RAM comes in different speeds, which can help with overclockers who want to push their systems, etc.
So thats why that stuff would be cheaper, and DDR PC2700 isn't the fastest RAM around so thats why its also a little cheaper, though this seems the fastest your laptop can support, and laptop parts tend to cost a bit more than standard parts anyway.
So just check the $199.99 one, and tell me that this isn't rated at way above PC2700 as the clock speed
I'm not sure if you could, but wouldn't it be rather simple to set up yourself? Does it have a slot? Or would you have to open the laptop up? and if so, are you sure its possible to change the memory amount in that case?
I hope this helps