No matter the size of your lawn, you could landscape for free or for very little money. You can find most things for free, if you watch the Super Saver section of the newspaper or any other local newspaper or website such as Craigslist.org. Change the current landscape by adding different plants, by completely changing plants or adding things picked up for free or inexpensively from yard sales.
Free plants are all over the place--you could trade with your neighbors for plants you no longer want, or you could get free plant cuttings from friends and neighbors. Many plants grow "babies." Often a homeowner throws the babies away because she doesn't want the plant to spread to other parts of her landscaping. Ask your friends and neighbors for any babies they are throwing away. Plant babies or cuttings in pots. Once they become established (in the case of cuttings) or grow to 6 inches or higher, transplant into your landscaping.
You can find free mulch in local newspaper ads and on Craigslist.org. Mulch not only dresses up the landscaping, but it is healthy for plants. It keeps moisture around the roots, which helps save on water usage. Mulch comes in various forms, from raw manure from farms, to pulverized bark from a homeowner trimming his trees. Often people have rubber mulch and want to change the type of mulch and advertise the mulch for free just to get rid of it.
Check newspaper advertisements for different types of supplies to build borders. People often give away wood from tearing down a building on their property, old pavers, stone, and various other materials that might be difficult to discard. If you live in a rocky area, find rocks to use as borders or place larger rocks in strategic places in the landscaping to "break up" the area.