Macro filters screw on to the end of your lens, and work a bit like a magnifying glass, making it able for you to achieve the macro effect, without having to buy an actual macro lens. Yay! They come in different sizes too. I got the set to fit my 50mm lens.
I decided to give the Polaroid ones a whirl after reading about them on Kaylah's blog some time ago. She'd recommended them for photos of insects and mushrooms, so I thought they must be pretty good for all sorts of small subjects.
As the +10 is the most extreme close-up filter, I've only used that one so far. I'm sure the other three will have their uses for some subjects, though. I think they'll be useful for some of my nail art photos, for example.
Obviously, I can't compare these to what a real macro lens could produce, but I am so impressed with the quality of them, and of the photos. For £14.99, they are an absolute bargain! I can't see a need for me to get a macro lens anymore. I definitely recommend them if, like me, you want to dip your toes into the world of macro photography, but don't want to pay very much. :)