There's an old joke among gardeners that taking an interest in perennials is a sign of maturity. Certainly those who plant lots of annuals every year begin to envision nickels, dimes, quarters and even dollar bills poking out of the soil. Among living things, you tend to get what you pay for. The canny gardener, however, knows that there are several ways to insure that bargain plants are truly bargains. Knowing how to use potential sources of cheap plants and ornamental grasses lets you fill your yard with beauty, without breaking the budget.
Buy plants at your supermarket or home center at the right time, to get inexpensive plants in good condition. Since markets and home centers sell plants only from time to time, they will usually offer them as a seasonal special. Buy plants the first or second day of the special, while they are still fresh from the grower and have not yet been subjected to amateurish or inadequate care.
Watch local nurseries for plants on sale. Here it makes sense to "stalk" a rhododendron till the post-bloom price goes down. You can be certain that the plant you would like to buy on sale will be cared for well by people who know plants until it is sold. If you see sale nursery plants in bad condition, assume the nursery may not take great care of full-price plants either.
Read plant catalogs carefully, to be certain a low price is really a bargain. The picture looks lovely, and the text raves. Your bare-root 2-year-old woody shrub, however, may be disappointingly tiny or arrive damaged by shipping delays. Put in a small order first, as a good reality check on the company's catalog promises, including return policies. You can always go back for more if you're pleased.
Scout out local sources for inexpensive plants. Locate your community's garden club, nature center or native plant organization. If they don't have plant sales themselves, they can be excellent sources for reputable and specialized nurseries and plant exchanges. Especially if you are looking for a rare native, what may seem like a high price to someone else may seem like a bargain in terms of the search. Local groups may also have good inexpensive ideas that have not occurred to you.
Contact almost-free "free" websites. Free-Trees-and-Plants provides employment to disabled workers; plants are free and you pay only shipping. The Arbor Day Foundation will provide you with a selection of trees that do well in your area in exchange for a low membership fee. The America the Beautiful Fund recycles unsold seeds of many varieties; you can choose categories in lots of 100 packets for a small contribution.
Cruise the increasing number of greenmarkets in your area. Perhaps not even knowing the farmer's name will make you eat more beets, but some greenmarket vendors offer plants as well as produce. If they don't, ask--new vendors especially enjoy learning what their customers would like to buy.