I ask dealer for coolant cap part number, they say it's called a bleeder valve?
 

I've driven myself nuts so I'm here for help.
My '99 base has a little bit of fluid by the coolant tank cap and the level was a little low so I said fine, gonna get some coolant and a new cap. I get the coolant and the dealer says cap is not in stock. I say ok could I have the part number. This was after telling him what i saw. He prints out a sheet and hands it to me, saying that they call it a bleeder valve. I say ok and take the paper without looking at it. I'm home now and the paper says bleeder valve, $125 and part number 996-106-347-02. I thought ok they screwed up so I will find one on the internet. There's a million of them out there and all sorts of prices and I don't want to get the wrong one, could a couple of you suggest a reputable vendor and part number? The kind that doesn't cost $125 oh my god! Thank you!

This is the link to the latest rev (.04) coolant cap for your car. (Qualifier goes here, I believe) Suncoast Porsche Parts & Accessories Coolant Cap

The bleeder valve is under the the plastic cover below the oil and coolant caps.

PN 996106447-04

The -04 is the latest version. $10-$35.

The cap is part #26 in the diagram in the link below;

986 Cooling System

Wow, so fast, thanks everyone! By the way, I do have a bentley manual and the only part number in there was for a "Two-stage" cap. Didn't see a number for a regular one.
Thanks again!!