African violet seeds are fun to sow and grow because you can never be sure what the plants or flowers will look like. Every seed represents a surprise. If you create your own African violet seeds through hybridizing you may have a rough idea of what traits the resulting plants will have. But if you buy mixed African violet seeds, all bets are off!
Where can you buy African violet seeds? Certainly not on the rack at the local garden center. African violet seeds are often available through the seed fund of the Gesneriad Society (membership required) and I highly recommend joining, if only for the seed fund and the magazine subscription that comes with membership.
If you are interested in growing other indoor plants from seeds: