Gerber daisies (aka gerbera daisies) are originally from Africa where they grow as a perennial. If you live in a temperate zone, you will probably have to grow them as an annual, usually started from seeds. You can grow your own gerber daisies and harvest the seeds to use for next years plants. Gerber daisies can be a little finicky in their requirements, but will certainly produce viable seeds if you take care of them properly.
Start by purchasing a couple of healthy plants from your local garden center. Look for one that has the traits that you like, such as color and length of stem. Bring them home and, assuming that the weather is warm, plant them in your garden in a sunny spot that gets full sun for about 12 hours a day.
Fertilize them every week with a balanced liquid fertilizer that will provide the nitrogen they need for quick plant growth, the phosphorus for good root production, and potassium for flower production and strength of the plant. This can be a compost tea or a good organic-based fertilizer as well. Make sure you rinse any fertilizer off the leaves of the plant, especially while it is young as it can burn the leaves.
Keep the soil pH balanced as close to seven as possible, adding lime if necessary to neutralize excess acid that can be caused by fertilizers. You can check it with a simple soil testing kit found in most local garden centers. Applying a good composted mulch to the soil will also keep it in good health. Just make sure not to cover the crown of the plant.
Watch the blossoms. They should be attracting bees for good pollination. Once the blossom fades and dries, collect the seed head by clipping it off just below on the stem. Open the dried seed head to inspect the seeds. Some will be thin and non-fertile while others will have a thicker middle portion. These thicker seeds are the ones you want to save for planting.
Place the dried freshly harvested seeds into a paper bag or envelope, label it and set it in a cool, dry, dark place for storage. The seeds will last for about three or four months before they start to lose their viability, so use them as soon as possible.