Ornamental grasses have become extremely popular in the past ten years or so, and if you buy them at a garden center they are kind of pricey. Learning how to grow them yourself is actually quite easy. They can be grown from seed, but I wont pretend to be an expert at that for several reasons. One, I dont know anything about growing them from seed, and two, I have no desire to propagate them from seed because seedlings require too much care.
The easiest and most effective way to propagate them is through simple division. Of course you will need at least one parent plant of each variety that you would like to grow. If you shop around you might be able to find some 4 inch pots at a fair price.
One of each variety is good for a start. I find that the best time of the year to divide them is in the spring, just before the new growth emerges. If you buy the stock plants in the early spring, you might be able to divide them right away. If you buy them at any other time of the year, just plant them in your garden or other suitable location, knowing that you are going to dig them up in a few months, or a year or so.
When spring arrives you can divide them at any time...