One method of delving into macro photography is to use adapter rings.
These rings have threads on both sides, one end is screwed onto your present camera lens like any filter and a second lens is attached in reverse onto the other end of the ring
You can buy these adapters or you can make them yourself
You may find filters in the clearance bins at some of the larger photography stores
for as little as one dollar
1) plastic bag, 2) safety glasses, 3) gloves, 4) pliers, 5) file, 6) hammer, 7) epoxy and mixing materials, 8) 2 filters
The magnification attained will be relative to the ratio of the focal length of the two lenses being used
0.5X=50mm (forward lens) / 100mm (reversed lens)
1X=50mm (forward lens) / 50mm (reversed lens)
2X=100mm (forward lens) / 50mm (reversed lens)
4X=200mm (forward lens) / 50mm (reversed lens) and so on.
clipped from: www.diyphotography.net 
