That will depend on whether or not you want to plant seeds or seedlings and the varieties you want to plant.
For such varieties as the regular African, French and/or dwarf very often the seed stores (and even dollar stores) will have racks of seed packets 8 or 10 for $1.00. Now I have used these inexpensive packets for over thirty years with excellent results.
The fancier varieties such as will require you switch up to some of the better known brand names.
You can also order through various seed catalogs which I will cover in another page. I have ordered seeds and plants from these catalogs for over thirty years with excellent success and have received great customer service as well.
You may choose to purchase seedlings, instead of planting seeds. Usually these are available through any good flower/home and garden center. You can buy some packets of six flowers or entire flats with dozens of seedlings in them.
Here are some tips on purchasing seedlings:
When starting a new garden, or adding to an existing one,
it is absolutely vital to choose only the healthiest plants from the best sources. While many gardeners prefer the control that can only be had by growing plants directly from seed, others prefer to buy seedlings or seed packs from a reputable nursery or garden center.
When buying seedlings to transplant,
it is essential that the gardener choose only the healthiest and most robust plants. If you are new to the gardening world, be sure to seek advice from more experienced gardeners with regards to the best places to buy healthy plants. Knowing where to buy, and what to look for once you get there, will give you a great start toward gardening success.
Be sure to look over the nursery or garden center
carefully and make an assessment of the health of the plants for sale. Do they have a robust look, with lush foliage and strong stems? Are they free of insects and disease? Be sure to look for any signs of disease, including spots on the leaves, holes, or scarring on the branches or stems.
Each flower variety you buy should come with instructions
for how to best transplant and take care of the plant. If such instructions are not provided, be sure to ask the staff at the nursery for recommendations. Following the recommendations and tailoring your care to the needs of each individual plant is the best way to succeed.