Macro lens for Nikon D40?

Looking for a reasonable priced Macro lens for my Nikon D40 with 18-55mm lens.
I have found a few on ebay but unsure to whether they are compatible and the pros/cons.
Your help and advice would be greatly appreciated.
I have attached the Ebay link also… (this is just one of them)

http://www.ebay.com.au/...0675831797

Added (1). Http://www.ebay.com.au/itm/290522501015

also this one above. If you could advise me on any on ebay as i would like to purchase one on there.

They are adapters, NOT lenses. The edge sharpness is suspect and you will NOT be happy with the results. These toys are aimed at intelligent but otherwise uninformed new photographers who are looking for a "deal". If you had taken even a basic class in photography, you would know that one lens can't be at one time a WIDE ★ FISH EYE ★MACRO★ lens, at least not for under $40

A true fisheye lens costs just under $775.
A wide angle lens like a 10-24 mm costs $900
and the two macro lenses listed below cost $280 or $600

Here are two you should consider, but you will have to save your pennies.

http://www.nikonusa.com/...F2.8G.html

or

http://www.nikonusa.com/...8G-ED.html

A true macro lens is one that is a flat field lens that can produce 1:1 image to subject ratios.

If your goal is to waste your money and degrade your image quality then by all means buy the worthless item you referenced. All it is is a piece of cheap glass of dubious optical quality that screws onto the front of your lens.

In my opinion your money would be better spent on a photography class or on a couple of books about photography. 'Understanding Exposure', 'Understanding Shutter Speed' and 'Understanding Photography Field Guide', all by Bryan Peterson, would be good choices.

Optimized image quality for Digital SLR cameras. Floating Internal Focusing (FIF) system minimizes the aberration in entire focusing range. Super Multi Layer (SML) coating reduces the ghost caused by reflections from the surface of digital image sensors. Minimum aperture of F/32 provides greater depth of field A screw-in hood for convenient use of circular polarizing filters MACRO 50mm F2.8 EX DG incorporates the very latest optical technology and is an ideal standard lens for digital SLR cameras. The new advanced lens design corrects various aberrations.