Which focusing screen for Nikon D5000? - 1

Hi, I'm new to the whole focusing screen concept, and so have no idea which one to buy, any suggestions would be great,
I have a Nikon D5000, no real budget, but under £100 would be nice.
Also, Amazon links would be helpful

Added (1). A focusing screen is to help with manual focusing

Added (2). Does have interchangeable focus screens

I have a D5000, and have no clue as to what you're talking about! " Focusing screen "?
You look through the viewfinder, frame & focus the shot, push the shutter button…
EDIT: and why do thumbs downers never answer a question?

I don't think your camera has interchangeable focusing screens.

If you want spit/micro prism focus screen, try KatzEye. Also look at the Plus Prism option as that will extend where the blackout region occurs if you have slow lenses.
http://www.katzeyeoptics.com/item--Nikon-D3000-D5000-Focusing-Screen--prod_D5000.html
The KatzEye site has instructions on how to change out your focus screen.

As an option, get used to using the focus good indicator in the lower left of your viewfinder. It's not as nice as a split prism, but it is useful.