The cheapest option which is the reversing ring holds a serious downside in that you have decoupled the aperture ring by reversing the lens so its all a bit trickier. You can easily see for yourself if you just hand hold the 50mm reversed onto the mount and try and take a picture. Do able but all a bit awkward. Also remember you will have no through the lens metering.
Closeup lens will be adding another glass element but you will retain all normal functions. I do not recognise the closeup lens you mention but a quick look at Amazon £25 for three of various diopters does not fill me with any confidence for that brand.
In general do closeup lenses work ..... yes. My neighbour Ros a member here has a Canon 350D with standard kit zoom. I made up an attatchment including the end of a flowerpot as a lenshood, fitted for a set of closup lenses from my Bronica days and she gets really good results.
Ros's gallery link
http://www.worldphotographyforum.com...user=2754&sl=r
That should show that quality closeups really work pretty well as a cheaper solution than a proper macro lens. You get what you pay for though with this sort of thing, so I would be looking at B+W or other quality manufacturer.
Don