How much should I sell my Nikon D40 for?

I bought it about 3 years ago and never got as into photography as I'd planned on so now I want to sell it. It is in like-new condition and comes with its original AF-S Nikkor 18-55mm lens and Nikon software CD. However I have lost the original box with the manuals. I originally paid around $600 I believe but I know that it is probably worth much less now, so how much should I ask for it?

Added (1). It also comes with the lens cap, charger, etc. Pretty much everything that came along with it when I bought it, except for the box and manuals.

Added (2). @ selina_555: You didn't answer my question at all but thanks for restating my "it is probably worth much less now" in four steps.

Here is what I found using the 'Advanced Search' feature on eBay:

Nikon D40 body only sold for $193.50

Nikon D40 w/18-55mm zoom, 2 batteries and an IR remote sold for $299.00

Nikon D40 w/18-55mm zoom and an after-market charger sold for $284.99

None of the 3 listings mentioned the manuals being included.

So I'd estimate that you might be able to get $250.00 or so for yours.

It sold for about $450 new in this area. I almost bought one.
$250 sounds about right for what you have.