I have Canon 600D and want to buy the cheapest and best Macro Lens. Which would be the best and cheapest lens for Macro photography? Please help! Thanks!
look also at sigma 105mm 2.8 EX if you agree on non canon lens (or 50 mm)
the 105mm give a good ratio (like the 100mm from canon) between deep of field / weight / distance to subject (especially without tripod where the canon with the IS have a big advantage if price was not considered like here)
EX version of sigma lens give a good quality (generally just under the L serie of canon with some flag lens, this 105 is not a flag lens but give excelent result with few aberation and an excelent 'piqué')
I often use it even without macro photo because it give a very interesting bocket ("blured background") compare to my 70/200 L serie.
Auto focus is not the fastest but help enough for macro shoot on "static" subject. On non macro photo, is is too slow and i often use the manual option when speedy focus is needed.
Until now, no specific problem or bad picture (due to lens :-D)
The 50 mm (I don't test) seems to be of the same kind cheaper
want to buy the cheapest and best Macro Lens
Seem a little bit difficult to satisfies both properties in one lens.
Personally I can recommend you the Canon EF-S 60mm 2.8. I own this lens by my self and I'm very happy about image quality. Disadvantage of the glass is that is sometimes hard to take a picture form small animals (bug, spiders, ...), because with this 60mm lens you have only very little minimum focusing distance when you want a 1:1 shot.
Canon offers at the moment (at least in some European countries) a cash back promotion. If you consider to buy this lens you should have a look for this.
The best macro lens in terms of usability, versatility, and image quality, will be a lens specifically designed as a macro lens for your system. In your case, the best macro lenses for a Canon 600D would be the Canon 60mm f/2.8 Macro EF-S, which is currently US$470, or the Canon 100mm f/2.8 Macro EF which is currently US$550.
If you are just starting out with macro photography, the cheapest way to get to true macro photography (1:1 or higher reproduction ratios) would be to use extension tubes or close-up lenses.
Extension tubes allow an existing lens to focus closer, but eliminate the ability to focus far away, reduce the light reaching the sensor, and often reduce you to manual focus and manual exposure.
Close-up lenses (sometimes called diopters) screw onto the front of your lens like a filter and act like a magnifying glass for the image. They also eliminate the ability the focus far away. But they tend to degrade the image by adding extra chromatic aberrations and more glass/air surfaces that can cause flare and unwanted reflections. Higher-quality close up lenses like the Canon 500D and 250D use Achromatic lenses to reduce chromatic aberration, but are much more expensive than the the typical close-up lenses.