You should have just gone to the recent outing at MOG and looked for me. I'd let you try the extension tube or close up filter, reverse adapter or even 100/2.8 macro

You will instantly know why ppl use a dedicated macro lens :bsmilie:
As Darrr said. The alternatives are cheap and can be good, but they all only focus along a limited range, so you will be 'stuck' with whatever field of view if gives.
A dedicated macro lens sllows you to shoot at any distance up to min focus distance allowing flexibility in composition.
Other stuff other than the above :
1. Close up filters : Typically poorer quality on the edges. Potential image degradation and light loss (typically minimal)
2. Extension tubes : cheap ones have no auto aperture making them very dark when stopped down for focusing purposes.
3. Reverse adapters : Typically gives very large magnifications. Downside of very close focus distances and very dark viewfinder when stopped down.
The alternatives are good if you are specialized or just want a simple close up option in the camera bag when travelling.