Growing by vegetative propagation.
When an african violet grows it continually produces new leaves. If you have one such plant and perhaps wish another two or three then you can take some of these leaves and propagate new plantlets.
Each plantlet will be a genetically identical organism to the "parent" plant.
Leaves should be taken from an already mature plant (Several leaves may be taken from the one plant but to ensure the original plant stays aesthetically pleasing, take the leaves from its base) A medium sized leaf blade with leaf stem fully intact is best. Check that the leaf, indeed the plant from which you are taking the leaf, is not diseased as this disease will be passed onto the new plant. Once certain you have a healthy stemmed leaf, you can set up the growing medium.
Some methods use water which has a little plant food in it to propagate african violets, but a small pot of soil, preferably one which is free from nitrates, herbicides, pesticides and fungicides is a good growth medium. African violets can be hard to grow in a soil which is too full of nutrients and although a little plant food is good for them, too much may kill them.
The leaf stem should be inserted almost fully into the soil, with just the leaf blade coming out of the soil. Water the soil well, but try to avoid wetting the leaves.
They should be kept out of direct sunlight but also should be kept at temperatures exceeding 65 degrees. A moist atmosphere will also aid their growth and they should be watered regularly.
It is prudent at this point to note that african violets take a reasonably long amount of time to show any signs of growth, from about 12 - 14 weeks before you will start getting actual leaf growth from the top of the stem where it was placed into the soil.
When the new leaves have reached the size of the original leaf, it should be cut off at soil level and the plantlet transferred to a larger pot.
Although this method is not as fast as the "store bought" method, you will find that you have a sense of achievement and also a number of healthy plants.