Believe me, within a year or so, those little plugs will be lovely good-sized clumps, as long as you plant them in full sun. Of course, if you can find locally, you get a larger plant without paying postage.

As watergal says, locally is best. But since local choices are usually limited to more popular grasses, mail order is a good option. Two online sources with extensive listings and plants of high quality and larger sizes are earthlypursuits.net in Maryland and bluestem.ca in British Columbia. Another source is the Magic Garden in upstate NY (magicgardenplants.com); their offering is small but selective, and their plants perform very well.

There are many other online sources that I have tried, mostly with success; email me if you need. You also might look around your area for OG gardeners to see if they have any newly divided grasses. I tend to avoid the "Big Box" stores, as the provenance of their plants is from nurseries in much warmer zones than mine.

If your interest in OGs is strong, I suggest you get yourself a good book on the subject. For my money, Rick Darke's "Color Encyclopedia of Ornamental Grasses" is the best (a book I often consult and find myself still reading an hour later).

I have purchased most of my ornamental grasses at local nurseries. However, most nurseries don't have much variety, so I recently ordered some prairie dropseed on-line from a nursery in Wisconsin that specializes in prairie plants. The grasses arrived in very good condition, just starting to grow, and were very inexpensive -- less than $4 each.

http://prairienursery.com/store/