Keep in mind, that photo is very tightly cropped, so my lenses did not capture it at that size. (See the original post for the full-size shot this was cropped from)
These are the lenses that I commonly refer to as "macro filters":
They are also referred to as diopters and close-up filters. After much consideration and research about how to dive into macro photography without breaking the bank, these filters are what I decided on, and I have been nothing short of pleased. You have seen many of the results on this blog and my other blog. I think this set cost me $25 US. They work best on a "short" (i.e. wide-angle) lens. I pair them with my 18-55mm lens. I tried them on my telephoto lens (55-200mm), and was never really able to get them to focus correctly.
The lenses can stack one on top of the other to give you ultimate magnification, but I have found that if I stack all 3 of them together, image quality actually suffers. I commonly stack the +2 and +4 filters together for my closest shots.
Here the +2 and +4 are stacked together to get a super-close shot of the +1 filter.
You'll notice "52mm" is printed on all of them. That is the filter attachment diameter of my two main lenses. This diameter differs by lens, so you need to find out what size lens you have if you decide to try something like this. You can find the filter attachment size listed in your camera manual.
If you have any questions, please feel free to ask.