If you have existing lenses, extension tubes and reversing rings offer simple, compact and affordable ways to get started in macro photography.
Placed between your camera and a non-macro lens, an extension tube allows your lens to focus at a closer range (depending on the tube’s thickness). Extension tubes do reduce the amount of light entering the lens (so you have to widen your aperture to compensate) and they tend to affect or rule out aperture and autofocus function.
Often used with the popular ‘nifty fifty’ (50mm prime lens), a reversing ring lets you attach a non-macro lens to your camera back to front. This has the same basic effect as a macro lens, i.e. capturing a small subject at a large scale. Edges can look soft but the results can otherwise be surprisingly good. Reversing rings may not be available for all camera brands, and some may rule out aperture and autofocus function.